2021 Australasian Sky Guide 9781863172172

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The Museum of Applied Arts and Sciences acknowledges Australia’s First Nations Peoples as the Traditional Owners and Custodians of the land and gives respect to the Elders — past and present — and through them to all Aboriginal and Torres Strait Islander peoples. Published annually since 1991 by Museum of Applied Arts and Sciences Media (formerly Powerhouse Publishing) Museum of Applied Arts and Sciences 500 Harris Street, Ultimo NSW 2007 maas.museum/store PUBLICATION MANAGER

Judith Matheson EDITOR Melita Rogowsky DESKTOP PUBLISHING Anne Slam DIAGRAMS AND ILLUSTRATIONS

Andy Chong/Picture This COVER DESIGN i2i Design PRINTING Ligare ISBN 978 1 86317 217 2 ISSN 2201–1765 Publication © 2020 Museum of Applied Arts and Sciences.

The Museum of Applied Arts and Sciences is an executive agency of the NSW Government. This book is copyright. Apart from fair dealing for the purposes of study, research, criticism or review, or as otherwise permitted under the Copyright Act, no part of this publication may be reproduced by any process without written permission. Inquiries should be made to the publisher.

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2021 AUSTRAL ASIAN SKY GUIDE

The author wishes to acknowledge the assistance and contributions made by staff at Sydney Observatory. The original monthly sky maps were prepared by Rod Somerville using the program Skymap. All material is supplied in good faith and is believed to be correct. It is supplied on the condition that no warranty is given in relation thereto and no responsibility or liability for error or omission is, or will be, accepted. At the time of publication, Daylight Saving Time ends in NSW, ACT, Victoria, South Australia, Tasmania and New Zealand at 3:00 am on Sunday 4 April 2021, when clocks should be turned back to 2:00 am. Daylight Saving Time begins again at 2:00 am on Sunday 26 September 2021 in New Zealand and at 2:00 am on Sunday 3 October 2021 in the relevant Australian states (see page 38 for more details). The information in this publication has been adjusted for summer time using the above times and dates. The tide predictions for Sydney (Fort Denison) have been formatted by Museum of Applied Arts and Sciences Media from material supplied by the Bureau of Meteorology. The Bureau of Meteorology gives no warranty of any kind whether express, implied, statutory or otherwise in respect to the availability, accuracy, currency, completeness, quality or reliability of the information or that the information will be fit for any particular purpose or will not infringe any third party Intellectual Property rights. The Bureau’s liability for any loss, damage, cost or expense resulting from use of, or reliance on, the information is entirely excluded.

CONTENTS HOW TO USE THIS BOOK

4

HIGHLIGHTS FOR 2021

5

THIS YEAR’S EVENTS

6

FUTURE EVENTS

MONTHLY STARS AND PLANETS

44

. December 2020

44

. January 2021

50

12

. February 2021

56

INDIGENOUS ASTRONOMY

13

. March 2021

62

THE SOLAR SYSTEM

16

. April 2021

68

. May 2021

74

THE MOON

34

. June 2021

80

TIME

38

. July 2021

86

THE SEASONS

39

. August 2021

92

THE SOUTHERN CROSS

40

. September 2021

98

2020 DAVID MALIN AWARDS

41

ANNIVERSARIES

42

. October 2021

104

. November 2021

110

. December 2021

116

FURTHER INFORMATION

122

AMATEUR ASTRONOMICAL SOCIETIES

123

OBSERVATORIES AND PLANETARIUMS

124

GLOSSARY

125

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HOW TO USE THIS BOOK Most of the astronomical information provided in this book is suitable for the whole of Australia and New Zealand. The descriptions of celestial events each month, such as the positions and movements of the planets, apply anywhere in the two countries. For local times of lunar eclipses and phases of the Moon in different time zones, just add or subtract the time difference; eg for New Zealand add two hours and for western Australia subtract two or three (depending on daylight saving in eastern Australia).

Rise and set times The rise and set times for the Sun, Moon and planets have been calculated for Sydney, but with suitable adjustments they can provide approximate times elsewhere. If you are close to the 34° latitude of Sydney, you can adjust the times for your location: take the difference between Sydney’s longitude of 151.2° East and the longitude of your location (you can find this on most maps), multiply by 4 and add the result in minutes. The tide tables apply to Sydney only.

Capital cities The following corrections are based on longitude differences and allow for daylight saving. For Melbourne, Adelaide, Perth and Auckland the possible errors with these adjustments will only be a few minutes. The errors will be somewhat larger for the other cities. 1 January to 3 April

4 April to 25 September

Adelaide

+20 min

Auckland

+26 min

Brisbane Christchurch

City

Darwin

26 September to 2 October

3 October to 31 December

+20 min

+20 min

+20 min

+26 min

+86 min

+26 min

–67 min

–7 min

–7 min

–67 min

+34 min

+34 min

+94 min

+34 min

–8 min

+52 min

+52 min

–8 min

Hobart

+16 min

+16 min

+16 min

+16 min

Melbourne

+25 min

+25 min

+25 min

+25 min

Perth

–39 min

+21 min

+21 min

–39 min

Wellington

+26 min

+26 min

+86 min

+26 min

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2021 AUSTRAL ASIAN SKY GUIDE

HIGHLIGHTS FOR 2021   Venus close to Saturn. With binoculars in the morning twilight the ringed planet Saturn can be seen close to Venus, the brightest of the planets (see page 58). 6–7 FEBRUARY

12 FEBRUARY   Venus close to Jupiter. Low in the morning twilight the brightest planet Venus passes the bright planet Jupiter (see page 58). 27 APRIL   Supermoon. At rising and setting, the full Moon appears slightly larger than usual (see page 6). 6–7 MAY   Eta Aquariid meteor shower. With only a waning crescent Moon in the sky there should be a good opportunity to view one of the year’s best meteor showers (see pages 7 and 75). 13 MAY   Daytime occultation of Venus. Only visible from parts of New Zealand, a very thin crescent Moon covers, or occults, Venus (see page 8). 26 MAY   Total eclipse of the Moon. A slightly larger Moon than usual moves into the Earth’s shadow and turns red (see pages 9 and 75). 29 MAY   Venus close to Mercury. The two innermost planets pass each other low in the evening sky (see page 76). 13 JULY   Venus close to Mars. Bright Venus passes the red planet in the evening (see page 88). 19 NOVEMBER   Partial eclipse of the Moon. The Moon rises already partially immersed in the shadow of the Earth (see pages 10 and 111). 4 DECEMBER   Partial eclipse of the Sun. Only visible from Hobart and Melbourne, this shallow eclipse takes place in the late afternoon (see page 117). 14–15 DECEMBER   Geminid meteor shower. The waxing gibbous Moon sets in time to allow a good opportunity to view one of the year’s best meteor showers (see page 11 and 117).

NASA's Perseverance rover will reach Mars and attempt to land at Jezero crater on 18 February. Courtesy NASA/JPL-Caltech

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THIS YEAR’S EVENTS   Supermoon. The Moon has an oval, or elliptical, path varying in distance from Earth approximately between 363,000 and 405,000 km. At its closest to Earth it is at perigee; at its furthest it is at apogee. When the full Moon is almost at perigee, it appears a little larger than usual. This has recently become known as a supermoon, though a better name would be full Moon at perigee. 27 APRIL AND 26 MAY

Comparison between the full Moon at its closest and its furthest from Earth. Photo/diagram Nick Lomb

A supermoon is not really an astronomical term as there are several possible definitions. Here we adopt the simple definition of a supermoon as when the full Moon is within 24 hours of perigee. There are two supermoons in 2021. On the 27 April, full Moon occurs 11 hours 53 minutes before perigee. On the 26 May, perigee occurs 9 hours 21 minutes before full Moon. Watching a moonrise during a full Moon is always good as, thanks to a psychological effect called the moon illusion, it appears larger near the horizon than higher in the sky. The table below gives the rise times of the two supermoons in local time in different cities. City

Moonrise on 27 April

Moonrise on 26 May

Adelaide

5:54 pm

5:06 pm

Auckland

5:53 pm

5:02 pm

Brisbane

5:34 pm

4:52 pm

Christchurch

5:52 pm

4:53 pm

Darwin

6:51 pm

6:20 pm

Hobart

5:36 pm

4:39 pm

Melbourne

5:54 pm

5:03 pm

Perth

6:01 pm

5:17 pm

Sydney

5:33 pm

4:46 pm

Wellington

5:47 pm

4:51 pm

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2021 AUSTRAL ASIAN SKY GUIDE

  The Eta Aquariid Meteor Shower. Each year around 6 May the Earth hits the stream of dust left behind by Halley’s Comet. These dust particles are ejected from the comet every 75 years or so when it approaches the Sun in its highly elongated path. Over time these tiny particles have spread out along the path of the comet so that when the Earth is near that path it collides with some of the particles. 6 AND 7 MAY

The particles from the comet are tiny — between the size of a grain of sand and a grain of rice — and they are light and fluffy, resembling ‘dust balls’. However, they are travelling fast, about 64 km per second, so that they have sufficient energy to create the streaks of light that we call meteors. These streaks occur about 100 km above our heads and are due to atoms in the atmosphere being excited by the impact of the particles. Each impact creates a tube of excited atoms that are less than a metre across but many kilometres long.

Observing in 2021 This year the peak of the shower is on the early mornings of Thursday 6 May and Friday 7 May. The waning crescent Moon is in the sky during both mornings but should not be bright enough to significantly affect viewing the meteors. The best view of the meteor shower is from a dark area, away from the direct view of street or other lights. The meteors can occur anywhere in the sky, though they all originate from a spot near the star Eta Aquarii. Finding chart for the Eta Aquariid meteor shower at 5:00 am on 6 and 7 May 2021.

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  Daytime occultation of Venus. Visible only from parts of New Zealand, this is the only occasion this year that the Moon covers, or occults, one of the five naked eye planets (Mercury, Venus, Mars, Jupiter, Saturn) as seen from Australia or New Zealand. It will be difficult to view as it occurs during daytime, when there is a lack of contrast between the surface brightness of the Moon and the sky, as well as between Venus and the sky. Nevertheless, it should be possible to see the occultation with the help of a pair of binoculars. 13 MAY

Those up for the challenge, should give themselves at least 30 minutes before the occultation to find the thin crescent Moon, and then Venus, by sweeping the area below and to the right or east of the Sun with binoculars. Extreme care must be taken not to point the binoculars at the Sun as that would create serious and likely permanent eye damage. The last occultation of Venus visible from Australia or New Zealand was another daytime event on 18 September 2017, when it was visible throughout both countries. There was also a daytime occultation of the other bright planet, Jupiter, on 23 January 2020. The table below lists the two cities from which the occultation is visible and gives the time of disappearance from Wellington and the reappearance of Venus from both. The times are local times. Note that as seen from Christchurch, Venus is already hidden behind the Moon at moonrise. City

Disappearance starts

Christchurch Wellington

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2021 AUSTRAL ASIAN SKY GUIDE

Reappearance starts

9:11 am 8:36 am

9:06 am

  Total eclipse of the Moon. A total eclipse of the Moon can be seen throughout Australia and New Zealand on the evening of Wednesday 26 May. During the eclipse, the Moon is likely to turn red due to light being refracted or bent around the Earth by our atmosphere. Unlike an eclipse of the Sun, eclipses of the Moon are completely safe to watch and can yield spectacular photographs, as shown by the one on this page. 26 MAY

The totally eclipsed Moon on 8 October 2014. Courtesy Russell Cockman

An unusual feature of this eclipse is that it occurs when the Moon is near perigee so that it appears a little larger than usual (see pages 6 and 126). The next eclipse of the Moon visible from Australia and New Zealand is a partial one on 19 November (see page 10). Eclipses of the Moon occur when the dark shadow of the Earth falls on the Moon. This happens when the Moon is full, as that is when the Sun, the Earth and the Moon are in alignment. However, a Moon or lunar eclipse does not occur every month, as the Earth’s shadow usually falls below or above the Moon. Circumstances in the different Australian and New Zealand cities are given in the table below. Times listed with an * are for 27 May. All times are local. City

Partial eclipse begins

Totality begins

Totality ends

Partial eclipse ends

Adelaide

7:15 pm

8:39 pm

8:58 pm

10:23 pm

Auckland

9:45 pm

11:09 pm

11:28 pm

12:53 am*

Brisbane

7:45 pm

9:09 pm

9:28 pm

10:53 pm

Christchurch

9:45 pm

11:09 pm

11:28 pm

12:53 pm*

Darwin

7:15 pm

8:39 pm

8:58 pm

10:23 pm

Hobart

7:45 pm

9:09 pm

9:28 pm

10:53 pm

Melbourne

7:45 pm

9:09 pm

9:28 pm

10:53 pm

Perth

5:45 pm

7:09 pm

7:28 pm

8:53 pm

Sydney

7:45 pm

9:09 pm

9:28 pm

10:53 pm

Wellington

9:45 pm

11:09 pm

11:28 pm

12:53 am*

2021 AUSTRAL ASIAN SKY GUIDE

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19 NOVEMBER   Partial eclipse of the Moon. A partial eclipse of the Moon can be seen throughout Australia and New Zealand, except from Perth, on the evening of Friday 19 November. The eclipse is almost total with 98 per cent of the Moon’s width immersed in the Earth’s shadow. Watchers in most cities can catch their first view of the eclipse with the striking sight of a reddish Moon rising with only a small part of its disc brightly lit by the Sun.

An almost totally eclipsed Moon on 4 April 2015. Courtesy Russell Cockman

The next eclipse of the Moon to be seen from Australia is on 8 November 2022. New Zealanders must wait another year until 29 October 2023. On average there are one and a half lunar eclipses each year with a maximum of three in a year. About half the eclipses are total eclipses, while the rest are only partial. Circumstances in different Australian and New Zealand cities are given in the table below. All times are local. City

Partial eclipse begins

Adelaide Auckland

Moonrise

7:59 pm 8:18 pm

Partial eclipse ends

9:17 pm 11:47 pm

Brisbane

6:14 pm

8:47 pm

Christchurch

8:29 pm

11:47 pm

Darwin

6:51 pm

8:17 pm

Hobart

8:13 pm

9:47 pm

Melbourne

8:09 pm

9:47 pm

Sydney

7:34 pm

9:47 pm

Wellington

10

8:18 pm

2021 AUSTRAL ASIAN SKY GUIDE

11:47 pm

  The Geminid Meteor Shower. Unlike the Eta Aquariids and all other meteor showers, the Geminids do not appear to be associated with a comet. Instead, their parent object is the rocky asteroid (3200) Phaethon, which is believed to be associated with one of the larger asteroids, (2) Pallas. 14 DECEMBER

Not surprisingly, the particles leading to the Geminid meteors appear to be made of denser and stronger materials than those of other meteor showers. This allows for brighter meteors during the shower. The asteroid’s path leads it much closer to the Sun than Mercury, so temperatures can reach 700°C on its sunward side. One theory of how it releases particles despite being an asteroid builds on this high surface temperature. The theory is that the large temperature change as the asteroid spins results in cracks on its surface and the production of dust-sized particles that cause the shower.

Observing in 2021 This year the predicted peak shower activity is on the mornings of Tuesday 14 December and Wednesday 15 December. Though the Moon is waxing gibbous it sets about two hours before nautical twilight, leaving a good opportunity to view the meteors before the sky brightens. Despite there being often bright meteors among the Geminids, it is best to view them from as dark a spot as possible. Use the finding chart below. Finding chart for the Geminid meteor shower at 4:00 am on 14–15 December 2021.

2021 AUSTRAL ASIAN SKY GUIDE

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FUTURE EVENTS   Total eclipse of the Sun. The track of totality for this eclipse grazes the Western Australian coastline passing over the North West Cape. Near the town of Exmouth, at about 11:30 am WST, totality will last just over one minute. The greatest eclipse is near the island of Timor with the track passing across the tip of East Timor. 20 APRIL 2023

The tracks across Australia and New Zealand of the 2023 and 2028 solar eclipses. Drawing by Andy Chong based on Google maps in the NASA eclipse website

22 JULY 2028   Total eclipse of the Sun. On this date Sydneysiders will have a once-in-a-lifetime opportunity to witness a fully eclipsed Sun from their own backyards. The Moon’s shadow will cut across the continent from north-west Australia to Sydney and then pass across the Tasman Sea to the southern part of New Zealand, directly over the city of Dunedin. Viewed from Sydney, the Moon will begin to block the Sun from 12:41 AEST, with almost four minutes of totality starting at 1:59 pm. 14 APRIL 2029   Close pass by asteroid. The asteroid (99942) Apophis is a 250-metre-wide rock that circles the Sun, mainly between the paths of Venus and Earth. On the morning of 14 April 2029, Apophis will come exceptionally close to Earth at a distance of about 40,000 km, which is approximately the height of communication satellites. Though the closest approach will not be visible from Australia or New Zealand, there will be a good view of it moving rapidly across the sky in the hours before dawn. 8 SEPTEMBER 2040   Planetary grouping. From our changing vantage point as the Earth circles the Sun, we see the planets take up different patterns along the ecliptic. Occasionally they appear close together in the sky. At this exceptionally close line-up, all five naked-eye planets will be less than 10° apart and will be easily visible in the western sky after sunset.

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2021 AUSTRAL ASIAN SKY GUIDE

ECLIPSES IN AUSTRALIAN INDIGENOUS ASTRONOMY In many Aboriginal cultures, the Sun is a woman and the Moon is a man. In Euahlayi traditions of northern New South Wales, Yhi (the Sun-woman) falls in love with Bahloo (the Moon-man), pursuing him across the sky. Bahloo is not interested in Yhi and rejects her advances, causing her to become overwhelmed with anger and jealousy. On rare occasions, she manages to catch Bahloo and tries to kill him in a fit of rage. When this happens, the Sun goes completely dark. This is a description of a total solar eclipse. Eclipses occur when the Earth moves into the narrow shadow of the Moon (solar eclipse) or when the Moon moves into the wider shadow of the Earth (lunar eclipse). In 2021, Australia will be treated to three eclipses: a total lunar eclipse on 26 May (see page 9), a partial lunar eclipse on 19 November (see page 10), and a partial solar eclipse on 4 December (see page 117). Total lunar eclipses are visible from across Australia about once every 2.8 years on average, but total solar eclipses are extremely rare, seen from any given location only about once every 350 years! Despite their rarity, all types of eclipses are well-known to Aboriginal and Torres Strait Islander peoples across Australia, whose detailed observations of celestial phenomena can be traced back thousands of years. For some Aboriginal communities, such as the Yolngu of Elcho Island in the Northern Territory, a solar eclipse is an act of love between the Sun-woman and Moon-man. On the west coast of South Australia, Wirangu people said the solar eclipse of 21 September 1922 was caused by the hand of Maamu-Waddi (a spirit-man), covering the Earth while the pair were guri-arra (husband and wife together). In Wiilman traditions of Noongar country in Western Australia, the Sun and Moon fell to Earth long ago, splitting it in half. The lazy people were separated from the rest of the community, forcing them to the other side of the Sun. Sometimes they get bored and want to see what is happening in this world. They tip the Sun on its side to have a peek, gathering around and blocking the Sun’s light, causing a solar eclipse.

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When sunlight enters our atmosphere, blue wavelengths of light are scattered (Rayleigh scattering), forming our blue skies. But during total lunar eclipses, redder wavelengths of light pass through our atmosphere, which are refracted onto the Moon like a lens (see page 10). This turns the Moon a deep red, sometimes referred to in English as a ‘blood moon’. In Luritja traditions of the Northern Territory, the Moon man eats the entrails of corpses during a lunar eclipse, then rises from the grave into the sky — covered in blood. Lunar eclipses are seen by many communities as a warning of danger, sickness, war, or death. In Kurnai traditions of Gippsland, Victoria, a lunar eclipse signifies that someone on a journey has been killed. In Kayardild traditions of Bentinck Island in the Gulf of Carpentaria, Queensland, the Moon-man collects the souls of the recently deceased during jawaaja (a lunar eclipse). As the net fills, the Moon-man gradually disappears, as if he has died. The people run and hide under fig trees — anyone caught out will be struck with jiljawatha (a sickness covering the body in sores). People from the northern Torres Strait island of Boigu (Talbot Island), in Queensland, refer to a lunar eclipse as meripal kulkan patan (blood covering the Moon). It’s a warning that raiders will attack, prompting the people to perform a sacred dance while wearing a special Moon-mask called a moelpalal dhoeri. People from the island of Moa (Banks Island), in the western Torres Strait, call a lunar eclipse merlpal maru pathanu (the ghost has taken the spirit of the Moon).

Peter Swanton is a Gamilaraay/Yuwaalaraay man from Mackay, Queensland, who graduated with a degree in astrophysics from the Australian National University in 2019. Duane Hamacher is Associate Professor of Cultural Astronomy at the University of Melbourne.

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2021 AUSTRAL ASIAN SKY GUIDE

Merlpal Maru Pathanu (the ghost has taken the spirit of the Moon), linocut by David Bosun, Moa Island (Banks Island), Queensland. Photo courtesy David Bosun

2021 AUSTRAL ASIAN SKY GUIDE

15

THE SOLAR SYSTEM The Sun Our nearest star is the Sun. It is the centre of our solar system and provides heat and light for the planets, asteroids and other objects that circle around it. Despite playing such a critical role in our solar system, the Sun is in fact a fairly average type of star, only one of over 100 billion in the Milky Way galaxy. The Sun is an enormous ball of gas, mainly hydrogen and helium, with no solid centre or surface. In its very hot centre regions, hydrogen nuclei (hydrogen atoms without the surrounding electrons) come together to form helium nuclei (helium atoms without the surrounding electrons). As each helium nucleus has slightly less mass than the four hydrogen nuclei that formed it, energy is released according to Einstein’s famous formula E = mc2, where E is energy, m is the mass loss and c is the speed of light. The energy slowly makes its way outwards from the centre. It is initially transferred in the form of radiation like the heat from an electric bar radiator, while closer to the surface the transfer is by cells of hot gas rising, cooling and then sinking. On its visible surface the Sun often shows dark spots. These sunspots are regions where strong magnetic fields inhibit the upward flow of heat and are therefore cooler and darker than the rest of the surface. Sunspots are only one example of activity on the Sun; huge explosions called flares release strong bursts of radiation, while coronal mass ejections throw large clouds of fast atomic particles into space. THE SUN FACTS Temperature of visible surface: 5500°C Temperature at centre: 15.7 million °C Diameter: 1.392 million km Period to turn around axis: 25 days (equator) Number of known planets: 8

NASA's Solar Dynamics Observatory recorded this energetic flare at the edge of the Sun in extreme ultraviolet light — light that is not visible to the human eye. Courtesy NASA/GSFC/SDO

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2021 AUSTRAL ASIAN SKY GUIDE

Mercury Mercury is the closest planet to the Sun and is named after the swift-footed messenger to the gods of Roman mythology. Of the planets that are visible with the unaided eye, Mercury is the hardest to see. This is because it always appears near the Sun and is often lost in its glare. We can only see Mercury when it is low on the horizon, just before sunrise or just after sunset. A strange fact about Mercury is that its day, the time from one sunrise to the next, is twice as long as its year, the time it takes to travel around the Sun. Because Mercury is so close to the Sun, it is extremely hot — up to 430°C on the side facing the Sun. But on the side facing away from the Sun the temperature falls to about –170°C. These temperature extremes are caused by the lack of a proper atmosphere. In January 2008, the National Aeronautics and Space Administration (NASA) Messenger spacecraft flew by Mercury for the first time since Mariner 10’s mission in 1975. Data collected by Messenger shows that lava ejected from volcanic vents is likely to have played a role in forming the planet’s surface. Scientists located a number of volcanic vents along the edges of the giant 1500-km-wide Caloris impact basin. Messenger’s images again confirm that the surface is crossed by hundreds of long cliffs called rupes (the Latin word for cliff). Rupes indicate faults in the crust of the planet caused by the contraction of the surface. Mercury has an iron core that makes up about 60 per cent of its mass. It appears that the planet shrunk due to the cooling of this large core. MERCURY FACTS Diameter: 4878 km Distance from Sun: 58 million km Period to travel around Sun: 88 days Period to turn around axis: 59 days Number of known satellites: 0

An enhanced colour view of Mercury made from images taken by the Messenger spacecraft to emphasise differences in surface composition. For example, light brown areas were formed by lava flows. Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

2021 AUSTRAL ASIAN SKY GUIDE

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Venus Venus, named after the Roman goddess of love and beauty, is the brightest object in the night sky, after the Moon. People often call Venus the Morning Star or the Evening Star because it is always seen just before sunrise in the east, or just after sunset in the west. The best time to examine Venus through a telescope is after sunset at twilight. Later, when the sky becomes darker, Venus appears so bright that sometimes our eyes cannot focus on it properly. No surface features can be seen due to the planet’s clouds, but we can see phases like those on the Moon. This is because Venus is always closer to the Sun than the Earth. Phases on Venus were first discovered by the Italian astronomer Galileo in 1610 and helped to convince him of the then revolutionary idea that the Earth circled the Sun. Venus has a thick atmosphere of mainly carbon dioxide with clouds of sulphuric acid. This dense atmosphere hides the surface from view and explains why Venus has the highest surface temperature of all the planets, 470°C. The atmosphere acts like a greenhouse, letting the Sun’s radiation in but not letting the heat back out. (Increasing levels of carbon dioxide in our atmosphere are concerning scientists about a ‘greenhouse effect’ on Earth.) One way of examining the surface of Venus is by using radar. This was done by the Magellan spacecraft, which mapped the planet during 1990–94. Scientists have named the newly discovered features after famous women of history and mythology. For example, the planet has a crater called Cleopatra and a large land mass called Aphrodite. VENUS FACTS Diameter: 12,104 km Distance from Sun: 108 million km Period to travel around Sun: 225 days Period to turn around axis: 243 days Number of known satellites: 0 A view of the northern hemisphere of Venus created from radar images made by the Magellan spacecraft. The colours in the image indicate the elevation of the surface. Courtesy NASA/JPL/USGS

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2021 AUSTRAL ASIAN SKY GUIDE

Earth Earth is the third planet from the Sun. With oxygen in its atmosphere and water in its rivers and oceans, its conditions are ideal for life. Some scientists think Mars may have harboured primitive bacteria in the distant past, but Earth is still the only planet we know has life. Earth moves around the Sun in a giant, nearly circular path 300 million km wide. The path is slightly elongated — Earth is 3 per cent closer to the Sun in the Australian summer than in winter. This does not cause summer or winter! It has a minimal effect compared to the effect of the tilt of the Earth, which is the real cause of the seasons. In summer the southern part of the globe is tilted towards the Sun, while in winter it is tilted away from the Sun. The only part of Earth we can study directly is its surface, but we have a good idea of what is inside. Scientists who have studied the vibrations made by earthquakes have confirmed that there is a solid core mainly made of iron at the centre of the Earth. Around this is an outer core mostly made of liquid iron. Electric currents in this liquid core give rise to Earth’s magnetic field and make a compass point in the right direction. Update: Researchers from the University of Illinois at UrbanaChampaign claim that the inner core has a slight spin relative to the rest of the Earth. Earthquakes called doublets, which originate from the same spot, produce seismic waves that penetrate to the inner core. The scientists say that changes over time in these waves indicate motion or spin. EARTH FACTS Diameter: 12,756 km Distance from Sun: 150 million km Period to travel around Sun: 365 days Period to turn around axis: 24 hours Number of known satellites: 1 One component of the doublet seismic wave (blue) penetrates the inner core, while the other component (purple) is reflected at its boundary. Courtesy Michael Vincent, University of Illinois at Urbana-Champaign

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Mars Because of its orange-red appearance in the night sky, Mars is often called the ‘red planet’. It derives its name from the Roman god of war. Mars is similar to Earth in a number of ways. A day on Mars is about the same length as a day on Earth. The tilt of Mars’ axis of rotation is also about the same as Earth’s — it therefore has similar seasons. Using a telescope, it is possible to see that the surface of Mars goes through changes in step with the change of seasons. This led people in the past to believe (incorrectly) that Mars had life, perhaps even a thriving civilisation. Today we know these changes are due to gigantic seasonal dust storms, which alternately cover and uncover darker areas of the surface. There is no liquid water on Mars. All water is frozen, either in the polar caps or in the soil as permafrost. Mars appears red because the iron-rich surface is rusted by the locked-up water. Close-up photographs of Mars have revealed winding valleys and channels, which have convinced most scientists that Mars had a thicker atmosphere and running water in the past. The best way to study Mars would be for geologists to visit the planet and roam its surface. However, it is a long, dangerous and lonely trip to Mars. The astronaut geologists would need to take several years’ supply of food, oxygen and medicines. They would also need huge quantities of rocket fuel for the return trip! MARS FACTS Diameter: 6787 km Distance from Sun: 228 million km Period to travel around Sun: 687 days Period to turn around axis: 25 hours Number of known satellites: 2

A view of Jezero Crater, the landing site chosen by NASA for its Mars 2020 Perseverance rover, which is planned to arrive on 18 February 2021. The crater rim stands out in the image, in which lighter colours indicate greater heights. The black oval on the left shows the targeted landing area. Courtesy NASA/JPL-Caltech/MSSS/JHU-APL/ESA

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Update: Phobos and Deimos are the two moons of Mars. A new theory of their origin indicates that in the past Mars has had prominent rings, like Saturn. The theory also explains the slight tilt of the orbit of Deimos with respect to that of Phobos and the equator of Mars.

Phobos, as imaged by the HiRISE camera (the most powerful camera ever sent to another planet) from NASA’s Mars Reconnaissance Orbiter on 23 March 2008. Courtesy

Asaph Hall, an astronomer at the US Naval Observatory in Washington discovered the two NASA/JPL/University of Arizona moons in 1877. They were named after the horses that pulled the chariot of the war god Ares, the Greek equivalent of the Roman Mars. Phobos means fear, while Deimos means flight or panic.

Phobos is the larger of the two irregular moons and circles and is closer to Mars than Deimos. Mars’ gravity is gently pulling Phobos closer to it and, in 50 million years or so, when the moon has lost enough height, gravitational forces will tear it apart into a ring. The new theory suggests that this has happened numerous times in the past with a new, smaller, moon forming each time from the ring-shaped debris of the previous one. When a new moon forms, interaction with the remaining material in the ring forces it to start migrating outwards, away from the planet. With time, it reaches an orbit where it circles Mars at exactly three times the rate of Deimos. Technically, it enters a three to one resonance with the outer moon and the two moons interact. During such an interaction in the past Deimos’ orbit was pushed into its current two-degree tilt. Calculations suggest that the interaction happened about three billion years ago with a moon about twenty times the mass of Phobos.

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Jupiter Jupiter is by far the largest planet in the solar system: 11 times wider than Earth, over 1300 times Earth’s volume and nearly three times as massive as all the other planets put together. It is a huge ball of gas with no solid surface and is the second brightest planet in the night sky (Venus is the brightest). Even through a small telescope you can see Jupiter as a disc flanked by its four largest moons: Io, Europa, Ganymede and Callisto. These moons are often called the Galilean satellites after their discoverer, the Italian astronomer Galileo. Due to its large size and strong gravity, Jupiter is the planet most likely to be hit by a comet. This was observed for the first time in July 1994 when Jupiter was bombarded by the fragments of Comet ShoemakerLevy 9. These fragments slammed into Jupiter at 200,000 km per hour, becoming extremely hot and forming fireballs as they plunged into the planet’s atmosphere. These fireballs rose thousands of kilometres above Jupiter and faded, leaving behind dark clouds. Jupiter’s most conspicuous feature is the Great Red Spot, which was first seen in 1664. This is a giant storm or cyclone that has lasted for over 300 years and has a width of 25,000 km, almost twice the size of Earth. It is spinning in a counterclockwise direction, indicating that, unlike cyclones on Earth, it is a high-pressure system. To astronomers, the Great Red Spot provides a laboratory for the study of weather patterns under unfamiliar conditions. JUPITER FACTS Diameter: 142,980 km Distance from Sun: 778 million km Period to travel around Sun: 12 years Period to turn around axis: 10 hours Number of known satellites: 79

NASA’s Juno spacecraft has been looping around Jupiter since July 2016 and will continue to do so until July 2021. Juno obtained this colour-enhanced image of the cloud bands and other features of Jupiter’s southern latitudes on 10 April 2020. Citizen scientist David Marriott produced the image from the raw data. Courtesy NASA/JPL-Caltech/SwRI/MSSS

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Update: Jupiter’s moon Europa, one of its four Galilean moons, is among the most intriguing places in the solar system thanks to its underground ocean. Scientists think that the underground ocean may have the right temperature and suitable chemicals for the existence of bacterial life. Reaching the underground ocean is currently too difficult but the moon’s icy surface gives clues about what is happening below.

This newly reprocessed image from NASA’s Galileo spacecraft shows a region of the moon Europa called Chaos Transition. Long ridges and blocks that have moved are visible in the image. Courtesy NASA/JPL-Caltech/

Europa was last imaged by the SETI Institute Galileo spacecraft over twenty years ago. Recently three Galileo images of the moon have been reprocessed using modern imaging techniques. Low resolution colour images of each region were mapped onto high resolution black and white images of the same region. The new images have enhanced colour highlighting different geological features and different surface chemical compositions. Light blue or white indicate areas of water ice, while reddish-brown areas likely show salts and sulfur compounds.

The newly processed images, like the one above, give a good view of Europa’s long ridges, which can be one to two kilometres wide, a few hundred meters high and thousands of kilometres long. These are fractures in Europa’s icy surface caused by the stretch and pull of Jupiter’s gravity, as the moon approaches and then moves away from the planet in its oval-shaped orbit. Also visible are bands formed by fractures stretched horizontally. Chaos terrain is an area with blocks from the surface that have been moved, rotated and tilted before being refrozen into their present state. In the image above, there is chaos terrain on the left-hand side with ridged plains on the right, giving rise to region’s title: Chaos Transition.

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Saturn According to Roman mythology, Saturn was the god of agriculture and father of Jupiter, king of the gods. Nine times the diameter of the Earth and 750 times its volume, Saturn is second in size only to Jupiter. In beauty it is second to none. Even through a relatively small telescope, Saturn can be seen as a bright disc surrounded by a spectacular ring. This ring was discovered in 1655 by the Dutch astronomer Christiaan Huygens. Later astronomers noticed that the ring was divided into three separate rings. In recent times Voyager spacecraft have shown that each of the rings seen from Earth is itself divided into thousands of narrow rings. The rings are made up of billions of icy chunks, ranging in size from a grain of sand to a large house. Although they stretch over 300,000 km, they are believed to be less than 1 km thick. Saturn’s largest moon, Titan, is one of the most interesting objects in the solar system, for it is the only moon around any of the planets with a significant atmosphere. This atmosphere is mainly made of nitrogen and some methane. It is so thick that it hid Titan’s surface from the cameras of the Voyager spacecraft. Saturn has 54 named moons, of which 12 were announced in 2005. Many of these moons interact with the rings and with each other in complex ways. For instance, Prometheus and Pandora act like shepherds to the outer F-ring. The gravitational pull of the two moons, circling Saturn just inside the ring and just outside respectively, prevents the ring from spreading out and so keeps it narrow. SATURN FACTS Diameter: 120,540 km Distance from Sun: 1426 million km Period to travel around Sun: 29 years Period to turn around axis: 11 hours Number of known satellites: 82

The Cassini spacecraft obtained this close view of part of Saturn’s rings on 6 July 2017. The true colour image shows narrow ringlets of width ranging from 40 to about 400 km in an area of the rings about 100,000 km from the centre of Saturn. Courtesy NASA/JPL-Caltech/ Space Science Institute

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The Cassini spacecraft is no more after it plunged into Saturn’s atmosphere on 15 September 2017. However, it has left a legacy of great discoveries and volumes of data that scientists expect to study for years to come. Some of the major discoveries concern the small moon Enceladus. Only 505 km across, it is now one of the prime candidates in the solar system for hosting life.

An artist’s impression of plumes being emitted from the vicinity of the south pole of Enceladus. The globe of the moon is based on a map compiled by the Cassini spacecraft. Courtesy

Cassini found that an area around the NASA/JPL-Caltech south pole of Enceladus, known as the ‘tiger stripes’, is ejecting water vapour and icy particles into space in jets with speeds of over 1000 km per hour. Some of these particles fall back on the moon so that its surface is exceptionally bright, in fact the brightest of any known object in the solar system. The remainder of the particles feed into Saturn’s broadest ring, the 300,000-km-wide E ring. Update: A team led by Scott S Sheppard of the Carnegie Institution for Science, in Washington DC, has discovered 20 new moons circling Saturn. The ringed planet has now surpassed Jupiter in the number of its known moons. The new moons were discovered using images taken with the Subaru Telescope on Mauna Kea in Hawaii, which is operated by the National Astronomical Observatory of Japan. Images are taken an hour apart near Saturn and the scientists examine them for objects that have moved during the time interval. These are then investigated further to determine their paths around the planet. Three of the new moons circle the planet in the same direction it spins so that they are prograde, while the other 17 circle it in the other direction, so that they are retrograde. Their inclinations to Saturn’s equator vary but match the inclination of previously known families of the planet’s moons. There are three main family groups: Inuit, Norse and Gallic. Each is believed to have originated in the breakup of a larger moon.

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Uranus In 1781 the musician and amateur astronomer William Herschel discovered the first new planet to be found since ancient times. It was named Uranus after the Roman god of the sky, who was the father of Saturn and grandfather of Jupiter. Uranus, like Saturn, has rings, but they are much thinner, narrower and darker. Astronomers discovered the main rings in 1977 as they watched Uranus pass in front of a star and saw the star blink on and off due to the rings blocking the starlight. Subsequently, a total of 11 rings were identified; more recently, the Hubble Space Telescope found two more. Both of these lie far away from the planet, with the span across the larger one twice that of the previously known rings. As rings continually lose the dust and other particles from which they are made, they can only survive for an extended period of time if they have a supply of new material. Discovered in 2003, a moon called Mab seems to be the source of fresh material for the planet’s largest ring. As small rocks moving around the solar system hit Mab, they blast dust from its surface and this dust settles on the ring. Astronomers using the giant Gemini North telescope on Mauna Kea in Hawaii have detected the ‘rotten egg’ gas hydrogen sulphide above the clouds of Uranus. This suggests that Uranus and Neptune were formed differently to Jupiter and Saturn, as they show ammonia but not hydrogen sulphide. The differences in composition give clues to the locations at which these giant planets were formed. URANUS FACTS Diameter: 51,120 km Distance from Sun: 2877 million km Period to travel around Sun: 84 years Period to turn around axis: 17 hours Number of known satellites: 27

A false colour view of Uranus taken with the Hubble Space Telescope to look for clouds in its atmosphere. About 20 were found. The image also shows the four main rings surrounding the planet and some of its moons. Courtesy NASA/JPL/STScI

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Neptune The existence of another planet beyond Uranus was first predicted in the 1840s to explain a difference between the observed and the calculated path of Uranus. The planet was found less than one degree from its predicted position, and the discovery was hailed as a brilliant achievement. It was named Neptune, after the Roman god of the seas. Nearly four times the diameter of Earth and 54 times its volume, Neptune is like a blue version of Jupiter. The blue colour is probably caused by the red in the Sun’s light being selectively absorbed by methane in Neptune’s upper atmosphere. Triton, with a diameter of 2700 km, is Neptune’s largest moon. It orbits Neptune backwards; that is, in the opposite direction to most of the other moons in the solar system. To astronomers, this suggests that Triton was formed elsewhere and later captured by Neptune. Update: Scientists have discovered a fascinating ‘dance of avoidance’ between two of the inner moons of Neptune. The tiny moons Naiad and Thalassa circle Neptune in paths separated by only 1850 km but they never get that close to each other. Naiad circles the planet every seven hours, while Thalassa, slightly further out, takes seven and a half hours. These two tiny moons avoid close approaches between them because Naiad’s path is slightly tilted and perfectly timed. NEPTUNE FACTS Diameter: 49,530 km Distance from Sun: 4508 million km Period to travel around Sun: 165 years Period to turn around axis: 16 hours Number of known satellites: 14

A Voyager 2 image of Neptune, taken as it was approaching the planet. It shows the Great Dark Spot in the centre of the planet’s disc and the small white cloud dubbed the Scooter below it. Courtesy NASA/JPL

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Dwarf planets Ceres was discovered on 1 January 1801 and named after the Roman goddess of agriculture. At first astronomers considered that it was a planet filling the gap between the orbits of Mars and Jupiter, but soon other objects were found circling the Sun in the same part of the solar system. A British astronomer coined the term ‘asteroids’ to encompass these objects. Ceres is the largest of the asteroids and its mass is about one-third of the total mass of all the asteroids. In August 2006 the IAU promoted it to dwarf planet on the basis that it has sufficient mass for its own gravity to pull it into a near-spherical shape. Until recently, Ceres appeared as no more than a small blurred dot even through the largest telescopes. That all changed with the arrival of NASA’s Dawn spacecraft at Ceres on 6 March 2015. Dawn has sent back pictures of a heavily cratered surface with collapsed structures and signs of landslides. In the southern hemisphere there is a cone-shaped 5-km-high volcano that emits water instead of lava. A new theory suggests that the volcano, Ahuna Mons, originated as a large bubble that emerged from the interior and pushed through a weakness in the crust in that region. The bubble, rising due to radioactive heating from below, would have consisted of salt water, mud and pieces of rock. All that sludge would have solidified into the mountain that we see today when it hit the cold of the exterior. CERES FACTS Diameter: 952 km Distance from Sun: 414 million km Period to travel around Sun: 1680 days Period to turn around axis: 9 hours Number of known satellites: 0

A false colour view of Ahuna Mons showing changes in elevation: brown represents the highest and blue the lowest. NASA’s Dawn spacecraft took the original images for this view from a height of just under 400 km above the surface. Courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

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Pluto was discovered by Clyde Tombaugh of the Lowell Observatory in Arizona in 1930. For many years it was seen as the ninth planet of the solar system. The first doubts arose in 1978 when an eagle-eyed astronomer noted it had a satellite. This was to be named Charon; it allowed the mass of Pluto to be measured and it turned out to be surprisingly small, about one-sixth that of the Earth’s Moon. By August 2006, when astronomers attending a meeting of the IAU in Prague were debating the definition of a planet, it was known that there were other objects circling the Sun beyond Neptune in similar paths to Pluto. Pluto was then demoted to dwarf planet as it had not ‘cleared the neighbourhood around its orbit’. Since NASA’s New Horizons spacecraft flew past Pluto on 14 July 2015 photographs have streamed back to Earth. The images reveal that the dwarf planet is much more geologically active than expected, considering its great distance from the Sun. One exciting discovery is that the giant ice plain Sputnik Planitia is kept young and without craters by a slow convection or churning of nitrogen ice ‘cells’. Scientists poring over photographs of Pluto have found evenly spaced ridges that resemble Earth's sand dunes at the edge of the ice plain Sputnik Planitia. The dunes are likely made of grains of frozen methane, which could have been arranged into the regular patterns by winds from nearby mountains. Sublimation — ice turning straight into gas — may have assisted the process. PLUTO FACTS Diameter: 2370 km Distance from Sun: 4437 to 7376 million km Period to travel around Sun: 248 years Period to turn around axis: 6.4 days Number of known satellites: 5

Evenly-spaced ridges can just be seen on the plain of Sputnik Planitia, to the right of the encircling mountains. Appearing just like sand dunes, they are believed to be made of frozen methane. Courtesy NASA/JHUAPL/SwRI

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Asteroids Asteroids are rocky objects circling the Sun that are either remnants of larger objects or have never been accumulated into a larger object. Unlike dwarf planets like Ceres (page 28), asteroids do not have enough mass and hence enough gravity to form into a near spherical shape. Most of them circle the Sun between the paths of Mars and Jupiter but some have paths near the Earth, while others exist at specific places on Jupiter’s path around the Sun.

Nightingale, the selected main site for sample collection from the asteroid Bennu, with an outline of the OSIRIS-REx spacecraft. Though located in a crater 140 metres wide, the safe landing area for the spacecraft is much smaller. Courtesy

Asteroid Bennu was discovered on NASA/Goddard/University of Arizona 11 September 1999 and was eventually given the official sequential number of 101955 (in other words, it is the 101955th asteroid to have been discovered). It is a dark, carbonrich asteroid with most of its materials dating back to the very early days of the solar system. Scientists think that it is a broken-off remnant from a much larger parent body that circled the Sun in the main asteroid belt between Mars and Jupiter. Bennu is only about 500 m wide, the same width as the span of Sydney Harbour Bridge, and it circles the Sun every 1.2 years.

Nine-year-old US school student Michael Puzio won an international competition to name the asteroid. His suggestion of Bennu refers to a bird of that name in Egyptian mythology, usually depicted as a grey heron. Puzo considered that the design of the NASA spacecraft — Origins, Spectral Interpretation, Resource Identification, SecurityRegolith Explorer (OSIRIS-REx) — then planned to be launched to rendezvous with the asteroid, resembled the bird. OSIRIS-REx has reached the asteroid and is examining it with a variety of instruments. The main aim of the mission is to retrieve a sample from the asteroid and return it to Earth. Initial observations are focused on finding a suitable site for a sample to be collected. Locating such a spot has turned out to be more difficult than expected because of the number of boulders covering the surface.

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Kuiper Belt objects Though the first object beyond Neptune, additional to Pluto, was only discovered in 1992, the Dutch American astronomer Gerard Kuiper had predicted the existence of a belt of such objects three decades earlier. Since 1992 many more objects have been found, including some comparable in size to Pluto with one, Eris, only just smaller. Scientists expect that there are hundreds of thousands of Kuiper Belt objects that are yet to be discovered. They represent a repository of frozen objects that are occasionally deflected into the inner solar system to become short-period comets.

An image of Arrokoth, as it would be seen by the human eye. It was produced from data obtained by NASA’s New Horizons spacecraft. Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Roman Tkachenko

Arrokoth is an asteroid circling the Sun in the Kuiper Belt, over 40 times as far from the Sun as the Earth. Ordinarily, we would know little about an object at that distance, but on 1 January 2019 NASA’s New Horizons spacecraft examined Arrokoth as it flew past. The spacecraft found that the asteroid is made up of two connected lobes. The recently given official name Arrokoth means sky in the language of the Native American Powhatan people of present-day eastern Virginia. The two lobes and the consistency of their appearance have led to a major scientific breakthrough. The New Horizons team have concluded that the lobes were once separate objects that approached each other, started circling and eventually gently merged. The gentle merging indicates that Arrokoth and other small solar system bodies were formed as part of the collapse of the original dust cloud surrounding the young Sun. The consistency of appearance and composition of the two lobes suggests that they were formed near each other from local materials. Neither of these observations is in accordance with the competing theory of the formation of small and large solar system objects that is based on the violent collisions of fast-moving particles and objects to create larger particles or objects.

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Comets Comets are lumps of frozen gases, such as water ice, ammonia and carbon dioxide, mixed in with space dust. Apart from rare comets like Halley’s Comet that are trapped in the interior of the solar system, they are generally found at its edges. The Kuiper Belt extends outwards from the orbit of Pluto and is likely to contain tens of thousands of these giant ‘dirty snowballs’. Pluto may, in fact, be just one of the largest and closest of these. Astronomers also think there is a cloud of billions of comets, called the Oort Cloud, surrounding the solar system and extending part of the way to the nearest stars. Every now and again one of the comets from the Kuiper Belt or the Oort Cloud approaches the Sun. Then spectacular things start to happen. The Sun’s heat turns some of the ice into gas and a huge cloud of released dust envelops the original comet. This is the ‘coma’ and is seen from Earth as a fuzzy blob. The other part of the spectacle is the tail. A combination of sunlight and charged particles emitted by the Sun push dust and gas from the comet into a tail that always points away from the Sun. Halley’s Comet was discovered when English scientist Edmond Halley recognised a comet he had observed in 1682 was the same as those that had been observed in 1607 and 1531. Halley’s Comet is the most famous of all comets, with the roughly 75 years between its returns punctuating human lifetimes. The most significant past return was the sighting in 1066 before the Battle of Hastings in which William the Conqueror defeated King Harold of England. During its most recent return in 1986 Halley’s Comet became the first comet visited by spacecraft. This includes the European Giotto probe, which flew into the comet’s coma and sent back images of its dark nucleus.

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A detail from the 11th century 70-metre British Bayeux Tapestry, showing a group of men marvelling at the object that later became known as Halley’s Comet. Courtesy Myrabella, Wikimedia Commons

Comet 2I/Borisov is the second known visitor to our solar system from interstellar space. Discovered by Crimean amateur astronomer Gennady Borisov on 30 August 2019, it has been identified as an interstellar visitor by its trajectory through the solar system. The trajectory is one that can only be followed by an object that is moving too quickly for it to be bound by the gravity of the Sun.

A Hubble Space Telescope image of Comet 2I/Borisov taken on 9 December 2019, only a day after the comet had made its closest approach to the Sun. The comet’s coma or dust cloud has been coloured blue to separate it from the background. Courtesy NASA,

The discovery of the first interstellar object, known as 1I/Oumuamua, was on 19 October 2017. But Oumuamua was already on its way out of the solar ESA, and D Jewitt (UCLA) system and there was little time for astronomers to make observations. Variations in its brightness suggested an elongated shape that was tumbling. Though there was considerable speculation of its nature, astronomers were satisfied that it had a purely natural origin. Unlike Oumuamua, Comet Borisov was still heading towards its closest approach to the Sun, on 8 December 2019. This gave scientists the time to turn the world’s major astronomical instruments towards the interstellar visitor to better understand its nature. These included the Hubble Space Telescope, launched into space in 1990, and the Atacama Large Millimeter/submillimeter Array (ALMA), an array of 66 radio telescopes in the Atacama Desert in Chile (currently the largest radio telescope in the world). Scientists using these instruments discovered that the comet is emitting far more carbon monoxide (CO) than a typical comet. CO is common in space and is generally found in cold places. This suggests this comet was formed near a red dwarf, a star that is much cooler than our Sun. One possible scenario is that while circling its star of origin Comet Borisov collided with or passed near a massive planet and was ejected from the system. It then began a lonely journey for millions, and possibly even billions, of years until it happened upon our solar system.

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THE MOON Distance At an average distance of 385,000 km from Earth, the Moon is our closest neighbour in space. That distance is the same as travelling ten times around the planet, a journey that would take a jet aircraft travelling nonstop about two-and-a-half weeks. Yet light from the Moon reaches Earth in only 1.25 seconds.

Appearance If we look at the Moon through a telescope we see that it is covered by craters — round depressions with raised rims — of all sizes. These are due to the impact of meteorites. Since there is neither wind nor rain on the Moon to wear away the craters, they preserve a record of the Moon’s bombardment from thousands of millions of years ago to the present day. By tradition, craters are named after scientists, philosophers and writers. In 1973 one small crater was named after the famous 19th-century Australian astronomer John Tebbutt. There are also giant dark regions on the Moon’s surface, which were once thought to contain water and so were misnamed maria (plural of the Latin mare meaning ‘sea’). The first crewed landing on the Moon in July 1969 was in Mare Tranquillitatis or the Sea of Tranquillity. Maria are regions where lava has covered low-lying basins carved out by huge impacts. They have fewer craters than other regions on the Moon because the lava flows occurred after much of the meteoric bombardment was over. Unlike the Earth, the Moon is not tilted with respect to the ecliptic, the plane of the solar system. This means that some elevated areas near its poles receive constant sunlight, while deep inside shaded craters water ice can remain frozen. Both the sunlight and the water will be welcome resources for future astronauts.

A map of the Moon’s south pole region showing the amount of sunlight at each spot. Courtesy NASA/GSFC/Arizona State University

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Observing the Moon Some of the Moon’s features such as the major seas can be discerned with the unaided eye, especially when the Moon is low in the sky and appears to be larger than usual. Of course, the view through a pair of binoculars or a small telescope is even better. The best time to view the Moon through a telescope is at first quarter phase, when deep shadows allow detail on craters and other lunar structures to be seen. The map below is shown with the correct orientation for viewing the Moon with binoculars. The table beneath gives the English names of the main features identified on the map, together with the key to the abbreviations. The map was created by lunar observer Harry Roberts.

Mare

Sea of

Abbreviation

Feature

Nectaris Fecunditatis Crisium Tranquillitatus Serenitatis Frigoris Humorum Procellarum Imbrium

Nectar Fertility Crises Tranquillity Serenity Cold Moisture Storms (Ocean of) Rains

RA Ap RV Alp SH A11

Altai Escarpment Apennine Mountains Rheita Valley Alps Southern highlands Apollo 11 landing site

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Phases of the Moon If we look at the Moon, we see that it shows phases; at times we see it fully, at other times only partly, or we don’t see it at all. These phases occur as the Moon has no light of its own so that all the light we see from it is reflected sunlight (see diagram below). One side is always lit by the Sun and we see different aspects of this lit side as the Moon circles the Earth each month. These phases are: New Moon — the time when the Moon is not visible. It becomes visible a day or two later as a thin crescent after sunset. First quarter — the time between the new Moon and full Moon phases, when half the Moon’s disc is visible. The Moon then rises around midday and sets around midnight standard time. Full Moon — the time when the full disc of the Moon can be seen. The Moon is opposite the Sun in the sky, so it rises when the Sun sets and sets when the Sun rises. Last quarter — The time between full Moon and new Moon, when half of the Moon is visible. The Moon then rises around midnight and sets around midday standard time. As the Moon circles the Earth it also spins on its axis at the same rate so that the Sum illuminates the whole of the Moon’s surface (apart from the poles) each month. Hence, a ‘day’ on the Moon lasts for a month. From the Earth, though, we only see one face of the Moon and it is only through spacecraft that we have seen the other side.

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Appearance of the Moon There are additional terms that are used to describe the appearance of the Moon. When more of the Moon is becoming visible, then it is waxing, while when less of the Moon is becoming visible, then it is waning. When less than half the Moon’s disc is visible, then it is a crescent, while when more than half is visible, then it is gibbous. These terms can be combined so that, for example, between full Moon and last quarter the Moon is waning gibbous.

A waxing crescent Moon at three-days old, taken with a small reflecting telescope and photographic film. Courtesy Russell Cockman

Other definitions related to the Moon: Apogee — the time when the Moon is at its furthest point from the Earth in its oval-shaped monthly path around it. Perigee — the time when the Moon is at its closest point to Earth in its oval-shaped monthly path around it. Blue Moon — the second full Moon in a calendar month (see page 9). Moon illusion — a psychological effect that makes the Moon appear larger and closer when it is near the horizon than when it is high up in the sky. Supermoon — the appearance of the Moon when the time of full Moon is close to the time of perigee (see page 7). Terminator — the line dividing the lit part of the Moon’s visible disc from the unlit part. When the Moon is waxing, everywhere along that line there is sunrise on the Moon and when the Moon is waning, everywhere along the line there is sunset. The resulting deep shadows along the line increase contrast on the surface and so provide the most detail when viewing the Moon through a telescope.

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TIME Our sense of time is based on the Earth’s daily spin about its axis. A day is the time the Earth takes to complete one spin. Some definitions relating to time are: Sunrise — the time when the top edge of the Sun’s disc appears above the horizon. Sunset — the time when the top edge of the Sun’s disc disappears below the horizon. Civil twilight — starts in the morning when the Sun’s centre is 6° below the horizon and finishes at sunrise. In the evening it starts at sunset and finishes when the Sun’s centre is 6° below the horizon. Generally, lights are needed for outdoor activities in the mornings before the start of civil twilight and in the evenings after its end.

A wooden owl clock with time indicated through the eyes of the bird. Mounted on the book of knowledge, it was made in Germany in 1929. MAAS Collection. Photo: Campbell Bickerstaff, MAAS

Nautical twilight — starts in the morning when the Sun’s centre is 12° below the horizon and finishes at the start of civil twilight. In the evening it starts at the end of civil twilight and finishes when the Sun’s centre is 12° below the horizon. Generally, the horizon is not visible in the mornings before the start of nautical twilight and in the evenings after its end. Summer time — all times in this guide are in Australian Eastern Standard Time (AEST) or summer time (AEDT), as appropriate. In 2021, summer time in NSW, Victoria, ACT, South Australia, Tasmania and New Zealand is expected to end on Sunday 4 April. In New Zealand it will begin again on Sunday 26 September, while for these Australian states the start date is Sunday 3 October.

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THE SEASONS The Earth takes approximately 365 and a quarter days or one year to complete its travel around the Sun. Its path is slightly elongated from a circle so that at its closest point to the Sun it is about 3% closer than at its furthest point. The closest point is known as perihelion, while the furthest point is known as aphelion. As the Earth travels around the Sun it is tilted by 23.5° to the vertical. It is this tilt that is responsible for the seasons and not the slight change in distance from the Sun during the year. There are four turning points associated with the seasons: Spring equinox — this takes place around 23 September each year. At this time neither hemisphere is tilted towards the Sun so that it appears to rise due east and set due west (see diagram below). As well, its centre is above the horizon for exactly 12 hours, though the day is a few minutes longer than 12 hours since sunrise and sunset involve the top edge of the Sun and not its centre. Summer solstice — this takes place around 22 December each year. At this time the southern hemisphere is tilted towards the Sun so that it rises south of east and sets south of west. It moves in a large arc across the sky, taking over 12 hours. Autumn equinox — this takes place around 21 March each year. At this time neither hemisphere is tilted towards the Sun so that, as discussed above for the spring equinox, it appears to rise due east and set due west. Winter solstice — this takes place around 22 June each year. At this time the southern hemisphere is tilted away from the Sun so that it rises north of east and sets north of west. It moves in a small arc across the sky, taking under 12 hours.

The arc of the sun at different times of the year.

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THE SOUTHERN CROSS Why do Australians and New Zealanders find the five stars of the Southern Cross so important? One reason is that they are particularly eye-catching — they are bright, close together and form a distinctive shape. They are therefore easy to find, and can be seen all year round in much of the two countries. How to find the Southern Cross: the diagram below shows how to find the Southern Cross in the sky. It is easy to find due to the brightness of its stars and the two bright stars (the pointers) that point to it. To use the diagram, face south and hold it in front of you with the arrow pointing down. It shows the position of the cross and the pointers for each month at about 8:00 pm (or 9:00 pm summer time). MAY

JUNE

APRIL

JULY

MARCH

AUGUST SOUTH CELESTIAL POLE

FEBRUARY

SEPTEMBER

JANUARY

OCTOBER

NOVEMBER

DECEMBER SOUTH

How to find south using the Southern Cross: the diagram shows how the long axis of the cross always points to the same point in the sky. This point is known as the South Celestial Pole. To find it, extend the long axis of the cross by four and a half times its length. South is the point on the horizon directly below the pole.

40

2021 AUSTRAL ASIAN SKY GUIDE

2020 DAVID MALIN AWARDS: WINNING SKY PHOTOS Sydney Observatory has a long association with astrophotography. Government astronomer Henry Chamberlain Russell began photographing the sky from the site in the early 1870s. His photographs of the Magellanic Clouds were acclaimed Winning photograph ‘Tranquility Base’ internationally. This tradition of by Mark Polsen. © Mark Polsen excellence continues today with an exhibition of top entries from the annual David Malin Awards, an astrophotography competition held by the Central West Astronomical Society open to Australian amateur astronomers and photographers. The competition aims to encourage photographers to use their vision, imagination and skill to produce inspiring and beautiful images of the sky. This year there were eight award categories: Wide-Field; Deep Sky; Junior; Nightscapes; Solar System; Animated Sequences: Scientific, Aesthetic; Themed Section: Astrophotography with your Smartphone. In addition, there is a Photo Editor’s Choice Award, an Australasian Sky Guide Cover Award and a discretionary Innovation Prize. The entries are judged by world-renowned astrophotographer Dr David Malin. The overall winner was Mark Polsen for ‘Tranquility Base’. Ross Giakoumatos won the 2020 Australasian Sky Guide Cover Award for ‘Comet SWAN (C/2020 F8)’, which features on the cover of this edition. Presented by the Central West Astronomical Society, the awards and exhibition are supported by CSIRO’s Astronomy and Space Sciences, and Sun Studios. The 2020 David Malin Awards exhibition is scheduled to begin at the CSIRO Parkes Observatory in September 2020. A travelling version can be seen at selected venues across Australia, beginning with Sydney Observatory in late 2020 (subject to change due to COVID-19 restrictions). Please check the website for details: maas.museum/sydney-observatory

2021 AUSTRAL ASIAN SKY GUIDE

41

ANNIVERSARIES The Australian solar eclipse expedition of 1871 There was a total eclipse of the Sun on 12 December 1871 with an eclipse track crossing the extreme north of Australia. The Royal Society of Victoria, in cooperation with the colonial governments of Victoria, South Australia, New South Wales and Queensland, organised an expedition to view the eclipse from its most accessible point, an island near the top of Cape York, Queensland.

A watercolour painting by Silvester Diggles of the steamer Governor Blackall at Eclipse Island (Morris Island), Queensland. Courtesy State Library of NSW

This cooperation was of great importance, as it was the first time the colonies had collaborated on a scientific enterprise. It was the first total solar eclipse since the invention of photography and the application of spectroscopy to the study of objects in the sky. So the expedition was to introduce Australian astronomers to the new field of astrophysics. The Royal Society of Victoria hired the steam ship Governor Blackall for the voyage. The ship left Sydney with 33 expeditioners aboard. They included the government astronomers of Melbourne Observatory and Sydney Observatory, Robert Ellery and Henry Chamberlain Russell, as well as other well-known astronomers. There were several other scientists on board. Among them were Charles Moore, the director of the Botanic Gardens in Sydney, the conchologist or collector of seashells, John William Brazier, and the naturalist and artist Silvester Diggles from Brisbane. There were also two photographers and a newspaper reporter. The naturalists took advantage of the Governor Blackall visiting two islands on the voyage north and collected many species of snails, shells, coral, green ants and other insects. With attitudes quite different to modern conservationists, they also shot and collected a variety of birds, often without even having an idea of their species.

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2021 AUSTRAL ASIAN SKY GUIDE

The expedition reached the small island that the astronomers designated Eclipse Island (now known as Morris Island) on 6 December 1871, only six days before the eclipse. The astronomers used the intervening time to set up their equipment, practice for the eclipse, and establish the exact geographical coordinates of the island.

Part of the Victorian party in front of one of their tents. Robert Ellery is third from left. Courtesy Museums Victoria Collections

Russell and his helpers set up their instruments in a large ‘Sydney tent’. Pride of place was given to the main telescope from Sydney Observatory, a Merz lens telescope with an objective lens of 18-cm width. Russell was planning to take photographs with this telescope and expected to make 20 exposures during the brief period of totality. The Melbourne party led by Ellery set up more instruments in a few smaller tents. Ellery and his fellow observers planned, not just to take photographs but, to observe the Sun with spectroscopes sent to Australia by the Eclipse Committee of the British Association for the Advancement of Science. The weather was fine for the first few days on the island and must have given Ellery, Russell and the others confident expectations for eclipse day. Sadly, cloud and rain descended two days before the eclipse and continued the morning of the eclipse. The astronomers could obtain only a few tantalising glimpses of the eclipsed Sun. Though the astronomers were unsuccessful, the naturalists had a most productive trip. The conchologist John Brazier reported the discovery of 11 new species of shells during the voyage. He named these new species after fellow members of the expedition including ones after Russell and Ellery. Reference • Nick Lomb, ‘Australian solar eclipse expeditions: the voyage to Cape York in 1871’, Journal of Astronomical History and Heritage, vol 19, iss 1, 2016, pp 79–95

Next year’s anniversary: the bicentenary of the Parramatta Observatory.

2021 AUSTRAL ASIAN SKY GUIDE

43

DEC

KEY







Bright Star

Faint Star Magellanic Cloud



MARS M JUPITER J

S SATURN

44

2021 AUSTRAL ASIAN SKY GUIDE

This sky map shows the ZODIAC CONSTELLATIONS, Non-Zodiac Constellations and Stars of the night sky as seen from Sydney at: 10:30 pm on 7 December 9:30 pm on 21 December For other dates subtract or add half an hour each week.

DECEMBER 2020 The evening sky See sky map opposite The summer constellation of Orion, the Hunter, is high in the northeast. The three stars in the middle of the constellation represent the belt of Orion. Above and a little further to the right or east of the rightmost star of the belt, we find a line of three faint objects, which make up the dagger or sword of Orion. In the middle is one of the most famous sights in the sky, the Great Nebula in Orion. From a city or suburban location, the ‘sword’ is best seen through binoculars. Extending a line through the stars of the belt towards the right or east, we reach Sirius, the brightest star in the sky. Extending the line in the other direction, we find Aldebaran, the brightest star in the constellation of Taurus, the Bull. Aldebaran’s outer layers are cooler than those of the Sun, so it has a noticeably orange colour. If we extend the line from Orion’s belt further to the left or west, we reach the Pleiades star cluster. To the unaided eye only six or seven stars are visible in the cluster, but through a telescope hundreds of them can be seen. They are at a distance of around 400 light years.

Meteor shower The Geminids are one of the year’s best meteor showers as seen from the southern hemisphere. This time there is an exceptionally favourable opportunity to view them without the Moon brightening the sky. To see the meteors, look towards the north on the early morning of Monday 14 December. A dark location away from street and other lights would provide the best prospect (see page 10).

DIARY FOR DECEMBER 2020

8

Tuesday

Last quarter

11:36 am

15

Tuesday

New Moon

3:16 am

21

Monday

Summer solstice

9:02 pm

22

Tuesday

First quarter

10:41 am

30

Wednesday

Full Moon

2:28 pm

2021 AUSTRAL ASIAN SKY GUIDE

45

Evening twilight Jupiter and Saturn have a close conjunction, while Mars is high in the northern sky. Mars is in the north in Pisces. On 23 December the gibbous Moon is above and to the left or west of Mars, while on the next evening it is still above but to the right or east of Mars. Jupiter is in the west in Sagittarius at the start of the month but follows Saturn into Capricornus just after the middle of the month. At the same time Jupiter and Saturn are getting closer with the giant planets appearing closest in the sky on 21 and 22 December (see page 11). On 17 December the crescent Moon is directly above Jupiter and Saturn. Saturn is in the west, moving from Sagittarius to Capricornus in the middle of the month.

Morning twilight Venus is low in the east. It starts the month in Libra, moves into Scorpius just after the middle of the month and then only five days later it is in Ophiuchus. On 13 December a thin new Moon is below and to the left or north of Venus.

9:00 pm on 17 December — Jupiter, Saturn and the crescent Moon

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2021 AUSTRAL ASIAN SKY GUIDE

DEC

Planets MERCURY Date

VENUS Set

MARS Rise

JUPITER

SATURN

Rise

Set

Rise

Set

Rise

Set

Rise

Set

1

5:03

18:59

4:12

17:34 15:32

3:03

9:03

23:09

9:14

23:17

2

5:04

19:03

4:12

17:36 15:29

2:59

9:00

23:06

9:11

23:13

3

5:05

19:07

4:12

17:39 15:26

2:56

8:57

23:03

9:07

23:09

4

5:06

19:11

4:12

17:41 15:23

2:52

8:54

23:00

9:04

23:06

5

5:07

19:14

4:12

17:43 15:20

2:49

8:51

22:56

9:00

23:02

6

5:08

19:18

4:12

17:45 15:18

2:45

8:48

22:53

8:57

22:59

7

5:10

19:22

4:11

17:47 15:15

2:42

8:45

22:50

8:54

22:55

8

5:11

19:26

4:11

17:49 15:12

2:39

8:42

22:47

8:50

22:52

9

5:13

19:30

4:11

17:51 15:10

2:35

8:39

22:44

8:47

22:48

10

5:14

19:33

4:11

17:53 15:07

2:32

8:37

22:40

8:43

22:44

11

5:16

19:37

4:11

17:55 15:05

2:29

8:34

22:37

8:40

22:41

12

5:18

19:41

4:12

17:57 15:02

2:25

8:31

22:34

8:36

22:37

13

5:20

19:45

4:12

18:00 15:00

2:22

8:28

22:31

8:33

22:34

14

5:22

19:48

4:12

18:02 14:57

2:19

8:25

22:28

8:29

22:30

15

5:24

19:52

4:12

18:04 14:55

2:16

8:22

22:24

8:26

22:26

16

5:26

19:55

4:12

18:06 14:53

2:13

8:19

22:21

8:22

22:23

17

5:29

19:59

4:13

18:08 14:50

2:09

8:16

22:18

8:19

22:19

18

5:31

20:02

4:13

18:10 14:48

2:06

8:13

22:15

8:16

22:16

19

5:33

20:06

4:13

18:12 14:46

2:03

8:10

22:12

8:12

22:12

20

5:36

20:09

4:14

18:14 14:44

2:00

8:07

22:09

8:09

22:09

21

5:39

20:13

4:14

18:16 14:42

1:57

8:05

22:05

8:05

22:05

22

5:42

20:16

4:15

18:18 14:40

1:54

8:02

22:02

8:02

22:02

23

5:45

20:19

4:15

18:20 14:37

1:51

7:59

21:59

7:59

21:58

24

5:48

20:22

4:16

18:23 14:35

1:48

7:56

21:56

7:55

21:54

25

5:51

20:25

4:17

18:25 14:33

1:45

7:53

21:53

7:52

21:51

26

5:54

20:28

4:17

18:27 14:31

1:42

7:50

21:50

7:48

21:47

27

5:57

20:31

4:18

18:29 14:29

1:39

7:47

21:46

7:45

21:44

28

6:01

20:34

4:19

18:31 14:27

1:36

7:45

21:43

7:42

21:40

29

6:04

20:37

4:20

18:32 14:26

1:34

7:42

21:40

7:38

21:37

30

6:08

20:40

4:21

18:34 14:24

1:31

7:39

21:37

7:35

21:33

31

6:11

20:42

4:22

18:36 14:22

1:28

7:36

21:34

7:31

21:30

2021 AUSTRAL ASIAN SKY GUIDE

47

DEC

Sun and twilight TWILIGHT START Date

Day

SUN

TWILIGHT END

Nautical

Civil

Rise

Set

Civil

Nautical

1

Tuesday

4:34

5:09

5:37

19:51

20:20

20:55

2

Wednesday

4:34

5:09

5:37

19:52

20:21

20:56

3

Thursday

4:33

5:08

5:37

19:53

20:22

20:57

4

Friday

4:33

5:08

5:37

19:54

20:23

20:58

5

Saturday

4:33

5:08

5:37

19:55

20:24

20:59

6

Sunday

4:33

5:08

5:37

19:56

20:24

21:00

7

Monday

4:33

5:08

5:37

19:56

20:25

21:01

8

Tuesday

4:33

5:08

5:37

19:57

20:26

21:02

9

Wednesday

4:33

5:08

5:37

19:58

20:27

21:02

10

Thursday

4:33

5:08

5:37

19:59

20:28

21:03

11

Friday

4:33

5:09

5:38

19:59

20:28

21:04

12

Saturday

4:33

5:09

5:38

20:00

20:29

21:05

13

Sunday

4:33

5:09

5:38

20:01

20:30

21:06

14

Monday

4:33

5:09

5:38

20:02

20:31

21:06

15

Tuesday

4:34

5:09

5:39

20:02

20:31

21:07

16

Wednesday

4:34

5:10

5:39

20:03

20:32

21:08

17

Thursday

4:34

5:10

5:39

20:03

20:33

21:08

18

Friday

4:35

5:10

5:40

20:04

20:33

21:09

19

Saturday

4:35

5:11

5:40

20:05

20:34

21:10

20

Sunday

4:35

5:11

5:40

20:05

20:34

21:10

21

Monday

4:36

5:12

5:41

20:06

20:35

21:11

22

Tuesday

4:36

5:12

5:41

20:06

20:35

21:11

23

Wednesday

4:37

5:13

5:42

20:07

20:36

21:12

24

Thursday

4:37

5:13

5:42

20:07

20:36

21:12

25

Friday

4:38

5:14

5:43

20:07

20:37

21:12

26

Saturday

4:39

5:15

5:44

20:08

20:37

21:13

27

Sunday

4:39

5:15

5:44

20:08

20:37

21:13

28

Monday

4:40

5:16

5:45

20:08

20:38

21:13

29

Tuesday

4:41

5:16

5:46

20:09

20:38

21:14

30

Wednesday

4:42

5:17

5:46

20:09

20:38

21:14

31

Thursday

4:42

5:18

5:47

20:09

20:38

21:14

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2021 AUSTRAL ASIAN SKY GUIDE

DEC

Moon and tides MOON

TIMES AND HEIGHTS OF HIGH AND LOW WATERS

Rise

Set

Time

H (m)

Time

H (m)

Time

H (m)

Time

H (m)

Date

20:40

6:00

3:02

0.51

9:32

1.77

16:09

0.39

22:04

1.33

1

21:37

6:43

3:37

0.54

10:09

1.78

16:48

0.38

22:45

1.30

2

22:30

7:32

4:15

0.57

10:47

1.78

17:30

0.40

23:29

1.27

3

23:19

8:27

4:57

0.60

11:29

1.75

18:15

0.42

9:27

0:15

1.25

5:42

0.64

12:13

1.71

19:03

0.44

5

0:03 10:29

1:07

1.24

6:34

0.67

13:02

1.67

19:57

0.45

6

0:43 11:34

2:05

1.25

7:34

0.69

13:58

1.62

20:53

0.44

7

1:19 12:39

3:08

1.30

8:42

0.69

15:00

1.58

21:49

0.42

8

1:52 13:44

4:10

1.38

9:55

0.66

16:07

1.55

22:43

0.39

9

2:25 14:51

5:07

1.50

11:08

0.58

17:14

1.53

23:34

0.36

10

2:58 16:00

6:01

1.64

12:16

0.48

18:16

1.52

3:33 17:11

0:24

0.34

6:52

1.77

13:20

0.37

19:16

1.51

12

4:12 18:23

1:12

0.34

7:43

1.89

14:18

0.27

20:14

1.49

13

4:57 19:36

2:00

0.36

8:33

1.97

15:14

0.20

21:10

1.46

14

5:49 20:44

2:49

0.39

9:23

2.01

16:06

0.18

22:04

1.42

15

6:47 21:46

3:38

0.43

10:13

2.01

16:58

0.20

22:57

1.38

16

7:50 22:39

4:28

0.49

11:00

1.95

17:48

0.25

23:48

1.34

17

8:55 23:24

5:17

0.55

11:48

1.86

18:38

0.32

9:59

4

11

18

0:40

1.30

6:07

0.61

12:35

1.74

19:27

0.41

19

11:00

0:01

1:31

1.27

7:00

0.68

13:22

1.62

20:15

0.48

20

11:59

0:34

2:24

1.27

7:55

0.73

14:11

1.49

21:01

0.53

21

12:55

1:03

3:18

1.29

8:57

0.77

15:04

1.39

21:47

0.56

22

13:50

1:30

4:13

1.33

10:04

0.78

16:03

1.32

22:33

0.57

23

14:44

1:56

5:05

1.40

11:14

0.75

17:05

1.28

23:18

0.57

24

15:39

2:23

5:52

1.47

12:17

0.69

18:02

1.26

16:35

2:51

0:01

0.56

6:36

1.55

13:11

0.61

18:55

1.27

26

17:33

3:22

0:43

0.55

7:16

1.62

13:56

0.53

19:42

1.28

27

18:31

3:58

1:22

0.55

7:56

1.69

14:37

0.46

20:26

1.29

28

19:29

4:39

2:00

0.54

8:33

1.76

15:15

0.41

21:07

1.30

29

20:24

5:26

2:39

0.53

9:12

1.80

15:54

0.37

21:47

1.31

30

21:16

6:20

3:18

0.53

9:51

1.84

16:33

0.34

22:29

1.32

31

25

Tidal predictions for Sydney only. Times are adjusted for daylight saving. © Commonwealth of Australia, Bureau of Meteorology, National Tidal Centre.

2021 AUSTRAL ASIAN SKY GUIDE

49

JAN

KEY







Bright Star

Faint Star Magellanic Cloud



MARS M

This sky map shows the ZODIAC CONSTELLATIONS, Non-Zodiac Constellations and Stars of the night sky as seen from Sydney at: 11:30 pm on 7 January 10:30 pm on 21 January For other dates subtract or add half an hour each week.

50

2021 AUSTRAL ASIAN SKY GUIDE

JANUARY 2021 The evening sky See sky map opposite The constellation of Orion is high in the north and dominates the evening sky. It is easily recognisable with four stars in a rectangular pattern, and three stars in a row in the middle representing the belt of the hunter Orion. Above the right or eastern part of the belt is Orion’s sword, made up of three fainter stars. If we extend an imaginary line through Orion’s belt to the right or east, we reach Sirius. It is an intrinsically bright star — about 25 times brighter than the Sun — and is also relatively close at a distance of only nine light years. Towards the left or west of Orion’s belt, we reach the orange-coloured star Aldebaran. This is a giant star with a surface temperature somewhat cooler than the Sun yet hundreds of times brighter. Aldebaran is the brightest star in a group of stars forming an inverted ‘V’ shape in Taurus, the Bull. Apart from Aldebaran, the stars of the group are part of a cluster of stars called the Hyades, which lies 150 light years away. Looking south we find that the Southern Cross, or Crux, is lying on its side in the south-east. There are four bright stars making up the Cross and a fainter fifth star that is becoming harder to see in the sky above over-lit cities. To astronomers the fifth star has been known as Epsilon Crucis, but the International Astronomical Union has now given it its own proper name, Ginan. This name comes from the Wardaman people of northern Australia to whom the star represents a red dilly bag filled with songs passing on knowledge. DIARY FOR JANUARY 2021

3

Sunday

Earth closest to the Sun (perihelion)

12:51 am

6

Wednesday

Last quarter

8:37 pm

13

Wednesday

New Moon

4:00 pm

21

Thursday

First quarter

8:02 am

29

Friday

Full Moon

6:16 am

2021 AUSTRAL ASIAN SKY GUIDE

51

Evening twilight Jupiter and Saturn disappear, leaving Mars as the only evening planet. Mars is high in the north-west, moving from Pisces into Aries at the end of the first week of the month. On 21 January the first quarter Moon is above Mars. Jupiter is low in the west in Capricornus, just above Saturn. It disappears below the horizon at the end of the first week of the month. Saturn is low in the west in Capricornus and precedes Jupiter below the horizon in the middle of the first week of the month.

Morning twilight Venus is low in the south-east, moving from Ophiuchus into Sagittarius at the end of the first week of the month. On 12 January a thin crescent Moon is above and to the right or south of Venus.

5:00 am on 12 January — Venus and the crescent Moon

52

2021 AUSTRAL ASIAN SKY GUIDE

Planets Date

VENUS Set

MARS Rise

JUPITER

SATURN

Rise

Set

Rise

Set

Rise

Set

Rise

Set

1

6:15

20:45

4:23

18:38 14:20

1:25

7:33

21:31

7:28

21:26

2

6:19

20:47

4:24

18:40 14:18

1:22

7:30

21:28

7:25

21:23

3

6:23

20:49

4:25

18:42 14:16

1:19

7:28

21:24

7:21

21:19

4

6:27

20:52

4:26

18:44 14:15

1:17

7:25

21:21

7:18

21:16

5

6:31

20:54

4:27

18:46 14:13

1:14

7:22

21:18

7:14

21:12

6

6:35

20:56

4:28

18:47 14:11

1:11

7:19

21:15

7:11

21:08

7

6:39

20:57

4:29

18:49 14:09

1:08

7:16

21:12

7:08

21:05

8

6:43

20:59

4:31

18:51 14:08

1:06

7:14

21:09

7:04

21:01

9

6:48

21:01

4:32

18:52 14:06

1:03

7:11

21:05

7:01

20:58

10

6:52

21:02

4:33

18:54 14:04

1:00

7:08

21:02

6:58

20:54

11

6:56

21:04

4:35

18:55 14:03

0:58

7:05

20:59

6:54

20:51

12

7:00

21:05

4:36

18:57 14:01

0:55

7:02

20:56

6:51

20:47

13

7:04

21:06

4:38

18:59 13:59

0:52

7:00

20:53

6:48

20:44

14

7:09

21:07

4:39

19:00 13:58

0:50

6:57

20:50

6:44

20:40

15

7:13

21:07

4:41

19:01 13:56

0:47

6:54

20:47

6:41

20:37

16

7:17

21:08

4:43

19:03 13:55

0:45

6:51

20:43

6:37

20:33

17

7:20

21:08

4:44

19:04 13:53

0:42

6:48

20:40

6:34

20:30

18

7:24

21:08

4:46

19:05 13:52

0:40

6:46

20:37

6:31

20:26

19

7:28

21:08

4:48

19:07 13:50

0:37

6:43

20:34

6:27

20:23

20

7:31

21:08

4:50

19:08 13:49

0:35

6:40

20:31

6:24

20:19

21

7:34

21:07

4:51

19:09 13:47

0:32

6:37

20:28

6:21

20:16

22

7:36

21:06

4:53

19:10 13:46

0:30

6:34

20:25

6:17

20:12

23

7:38

21:04

4:55

19:11 13:44

0:27

6:32

20:21

6:14

20:08

24

7:40

21:02

4:57

19:12 13:43

0:25

6:29

20:18

6:11

20:05

25

7:41

21:00

4:59

19:13 13:42

0:22

6:26

20:15

6:07

20:01

26

7:42

20:57

5:01

19:14 13:40

0:20

6:23

20:12

6:04

19:58

27

7:42

20:54

5:03

19:15 13:39

0:17

6:21

20:09

6:00

19:54

28

7:41

20:50

5:05

19:16 13:37

0:15

6:18

20:06

5:57

19:51

29

7:39

20:46

5:07

19:16 13:36

0:12

6:15

20:02

5:54

19:47

30

7:37

20:42

5:09

19:17 13:35

0:10

6:12

19:59

5:50

19:44

31

7:34

20:36

5:11

19:18 13:33

0:08

6:09

19:56

5:47

19:40

2021 AUSTRAL ASIAN SKY GUIDE

53

JAN

MERCURY

JAN

Sun and twilight TWILIGHT START Date

Day

SUN

TWILIGHT END

Nautical

Civil

Rise

Set

Civil

Nautical

1

Friday

4:43

5:19

5:48

20:09

20:38

21:14

2

Saturday

4:44

5:19

5:48

20:10

20:39

21:14

3

Sunday

4:45

5:20

5:49

20:10

20:39

21:14

4

Monday

4:46

5:21

5:50

20:10

20:39

21:14

5

Tuesday

4:47

5:22

5:51

20:10

20:39

21:14

6

Wednesday

4:48

5:23

5:52

20:10

20:39

21:14

7

Thursday

4:49

5:24

5:53

20:10

20:39

21:14

8

Friday

4:50

5:25

5:53

20:10

20:39

21:14

9

Saturday

4:51

5:26

5:54

20:10

20:39

21:14

10

Sunday

4:52

5:27

5:55

20:10

20:38

21:13

11

Monday

4:53

5:27

5:56

20:10

20:38

21:13

12

Tuesday

4:54

5:28

5:57

20:10

20:38

21:13

13

Wednesday

4:55

5:29

5:58

20:09

20:38

21:12

14

Thursday

4:56

5:30

5:59

20:09

20:38

21:12

15

Friday

4:57

5:31

6:00

20:09

20:37

21:12

16

Saturday

4:58

5:32

6:01

20:09

20:37

21:11

17

Sunday

4:59

5:33

6:02

20:08

20:37

21:11

18

Monday

5:00

5:35

6:03

20:08

20:36

21:10

19

Tuesday

5:01

5:36

6:04

20:08

20:36

21:10

20

Wednesday

5:03

5:37

6:05

20:07

20:35

21:09

21

Thursday

5:04

5:38

6:06

20:07

20:35

21:09

22

Friday

5:05

5:39

6:07

20:06

20:34

21:08

23

Saturday

5:06

5:40

6:08

20:06

20:34

21:07

24

Sunday

5:07

5:41

6:09

20:05

20:33

21:07

25

Monday

5:08

5:42

6:10

20:05

20:32

21:06

26

Tuesday

5:10

5:43

6:11

20:04

20:32

21:05

27

Wednesday

5:11

5:44

6:12

20:04

20:31

21:04

28

Thursday

5:12

5:45

6:13

20:03

20:30

21:04

29

Friday

5:13

5:46

6:14

20:02

20:30

21:03

30

Saturday

5:14

5:47

6:15

20:02

20:29

21:02

31

Sunday

5:16

5:48

6:16

20:01

20:28

21:01

54

2021 AUSTRAL ASIAN SKY GUIDE

Moon and tides TIMES AND HEIGHTS OF HIGH AND LOW WATERS

Rise

Set

Time

H (m)

Time

H (m)

Time

H (m)

Time

H (m)

Date

22:02

7:19

4:00

0.53

10:32

1.85

17:14

0.34

23:12

1.33

1

22:44

8:22

4:44

0.54

11:14

1.84

17:57

0.34

23:58

1.33

2

23:21

9:27

5:30

0.55

11:58

1.80

18:41

0.35

23:55 10:32

0:46

1.34

6:22

0.58

12:45

1.74

19:28

0.37

4

11:37

1:39

1.37

7:19

0.61

13:36

1.65

20:17

0.40

5

0:27 12:42

2:36

1.41

8:23

0.63

14:33

1.56

21:09

0.42

6

0:58 13:48

3:36

1.47

9:35

0.63

15:39

1.46

22:04

0.44

7

1:32 14:55

4:36

1.56

10:53

0.59

16:51

1.40

23:00

0.46

8

2:08 16:05

5:36

1.67

12:09

0.51

18:02

1.36

23:56

0.46

2:48 17:15

6:33

1.77

13:16

0.41

19:08

1.36

3:35 18:24

0:51

0.46

7:29

1.87

14:15

0.31

20:08

1.37

11

4:29 19:28

1:44

0.45

8:21

1.93

15:08

0.25

21:01

1.38

12

5:30 20:25

2:35

0.45

9:11

1.97

15:56

0.22

21:51

1.39

13

6:34 21:14

3:24

0.45

9:59

1.96

16:42

0.24

22:38

1.39

14

7:39 21:55

4:12

0.47

10:44

1.91

17:25

0.28

23:23

1.38

15

8:43 22:31

4:57

0.51

11:26

1.83

18:05

0.34

3

9 10

16

9:44 23:02

0:06

1.36

5:42

0.56

12:05

1.72

18:44

0.41

17

10:43 23:30

0:48

1.35

6:27

0.62

12:45

1.60

19:21

0.48

18

11:39 23:57

1:32

1.34

7:15

0.68

13:24

1.48

20:00

0.54

19

12:34

2:19

1.34

8:08

0.73

14:09

1.36

20:40

0.58

20

13:29

0:23

3:10

1.36

9:12

0.77

15:03

1.27

21:28

0.62

21

14:25

0:51

4:05

1.40

10:26

0.76

16:11

1.20

22:20

0.64

22

15:21

1:21

5:01

1.45

11:39

0.72

17:23

1.17

23:15

0.65

23

16:19

1:54

5:55

1.51

12:43

0.65

18:28

1.19

17:17

2:33

0:07

0.64

6:45

1.59

13:34

0.56

19:22

1.22

25

18:13

3:17

0:54

0.61

7:29

1.67

14:17

0.48

20:07

1.27

26

19:07

4:09

1:38

0.57

8:11

1.75

14:56

0.40

20:48

1.31

27

19:57

5:07

2:20

0.52

8:52

1.82

15:34

0.34

21:29

1.36

28

20:41

6:10

3:02

0.48

9:33

1.88

16:13

0.29

22:09

1.40

29

21:20

7:15

3:46

0.44

10:15

1.91

16:52

0.26

22:51

1.44

30

21:56

8:22

4:32

0.43

10:59

1.90

17:32

0.26

23:35

1.47

31

24

Tidal predictions for Sydney only. Times are adjusted for daylight saving. © Commonwealth of Australia, Bureau of Meteorology, National Tidal Centre.

2021 AUSTRAL ASIAN SKY GUIDE

55

JAN

MOON

FEB

KEY







Bright Star

Faint Star Magellanic Cloud



MARS M

This sky map shows the ZODIAC CONSTELLATIONS, Non-Zodiac Constellations and Stars of the night sky as seen from Sydney at: 10:30 pm on 7 February 9:30 pm on 21 February For other dates subtract or add half an hour each week.

56

2021 AUSTRAL ASIAN SKY GUIDE

FEBRUARY 2021 The evening sky See sky map opposite The February night sky is dominated by the constellation of Orion in the northern sky. At the top left or west of the constellation we find the star Rigel, which is the brightest star in the constellation although it is designated as the Beta star. The Alpha star is the reddish star Betelgeuse, at the bottom and right or east of the constellation. Betelgeuse, one of the few stars in the sky with an obvious red colour, is a giant star so big that if it replaced the Sun it would engulf Mercury, Venus, the Earth and even Mars. Extending an imaginary line through the three stars of Orion’s belt to the right or east, we reach Sirius, the brightest star in the sky and the brightest star in the constellation of Canis Major, the Great Dog. Below Sirius is the bright star Procyon, which is at a distance of only 11 light years and is a little bit bigger than the Sun. Its name comes from the Greek meaning ‘before the dog’, a reference to it rising before Sirius, the ‘Dog Star’, in the northern hemisphere. Taking the imaginary line through Orion’s belt towards the left or west, we reach Aldebaran, the brightest star in the constellation of Taurus, the Bull. Taking the line further, we reach the Pleiades star cluster. Most people can see six stars in the cluster, though some can see a fainter seventh star. Intriguingly, stories from a number of unconnected cultures refer to these stars as ‘seven sisters’. The Southern Cross, or Crux as it is known to astronomers, is lying on its side in the south-east with the two pointer stars below. Its five naked-eye stars are at different distances from us, ranging from 88 to 364 light years. DIARY FOR FEBRUARY 2021

5

Friday

Last quarter

4:37 am

12

Friday

New Moon

6:06 am

20

Saturday

First quarter

5:47 am

27

Saturday

Full Moon

7:17 pm

2021 AUSTRAL ASIAN SKY GUIDE

57

Evening twilight Mars is the only evening planet. Mars is in the north-west, starting the month in Aries but moving into Taurus during the last week. On 18 February the crescent Moon is to the left or west of Mars, while the next evening it is above and to the right or north of the planet.

Morning twilight Mercury appears low in the east from the middle of the month, moving two days later from Aquarius to Capricornus. Venus is very low in the east. It moves from Sagittarius into Capricornus at the beginning of the month and into Aquarius during the last week. On 6 and 7 February Venus passes Saturn at a separation of just over one moon-width; binoculars are needed to see the ringed planet. On 11 February a very thin crescent Moon is above and to the right or south of Venus. On 12 February, low in the twilight, Venus passes Jupiter at a separation of half a degree or one moon-width. Jupiter appears low in the east in Capricornus in the middle of the month. Saturn appears low in the east at the end of the first week of the month in Capricornus. On 10 February a thin crescent Moon is above Saturn. 5:45 am on 28 February — three planets

58

2021 AUSTRAL ASIAN SKY GUIDE

Planets MERCURY Date

VENUS Set

MARS Rise

JUPITER

SATURN

Set

Rise

Set

Rise

Set

Rise

Set

7:29

20:31

5:13

19:18 13:32

0:05

6:07

19:53

5:44

19:37

2

7:24

20:24

5:15

19:19 13:31

0:03

6:04

19:50

5:40

19:33

3

7:18

20:18

5:17

19:19 13:29

0:01

6:01

19:47

5:37

19:30

4

7:12

20:11

5:19

19:20 13:28 23:56

5:58

19:44

5:34

19:26

5

7:04

20:03

5:21

19:20 13:27 23:54

5:56

19:40

5:30

19:23

6

6:56

19:56

5:23

19:21 13:26 23:52

5:53

19:37

5:27

19:19

7

6:47

19:48

5:25

19:21 13:24 23:49

5:50

19:34

5:24

19:16

8

6:38

19:40

5:27

19:21 13:23 23:47

5:47

19:31

5:20

19:12

9

6:29

19:32

5:30

19:22 13:22 23:45

5:44

19:28

5:17

19:08

10

6:19

19:25

5:32

19:22 13:21 23:43

5:42

19:24

5:13

19:05

11

6:10

19:18

5:34

19:22 13:19 23:41

5:39

19:21

5:10

19:01

12

6:00

19:10

5:36

19:22 13:18 23:38

5:36

19:18

5:07

18:58

13

5:52

19:04

5:38

19:22 13:17 23:36

5:33

19:15

5:03

18:54

14

5:43

18:58

5:40

19:22 13:16 23:34

5:30

19:12

5:00

18:51

15

5:35

18:52

5:43

19:22 13:15 23:32

5:28

19:09

4:57

18:47

16

5:27

18:47

5:45

19:22 13:13 23:30

5:25

19:05

4:53

18:44

17

5:20

18:42

5:47

19:22 13:12 23:28

5:22

19:02

4:50

18:40

18

5:14

18:37

5:49

19:22 13:11 23:26

5:19

18:59

4:46

18:37

19

5:08

18:33

5:51

19:22 13:10 23:23

5:16

18:56

4:43

18:33

20

5:03

18:30

5:53

19:22 13:09 23:21

5:14

18:53

4:40

18:29

21

4:58

18:26

5:55

19:22 13:08 23:19

5:11

18:49

4:36

18:26

22

4:54

18:24

5:57

19:21 13:06 23:17

5:08

18:46

4:33

18:22

23

4:50

18:21

6:00

19:21 13:05 23:15

5:05

18:43

4:29

18:19

24

4:47

18:19

6:02

19:21 13:04 23:13

5:02

18:40

4:26

18:15

25

4:44

18:17

6:04

19:21 13:03 23:11

5:00

18:37

4:23

18:12

26

4:42

18:16

6:06

19:20 13:02 23:09

4:57

18:33

4:19

18:08

27

4:40

18:14

6:08

19:20 13:01 23:07

4:54

18:30

4:16

18:04

28

4:39

18:13

6:10

19:19 13:00 23:05

4:51

18:27

4:12

18:01

23:58

2021 AUSTRAL ASIAN SKY GUIDE

59

FEB

Rise

1

Sun and twilight TWILIGHT START

FEB

Date

Day

SUN

TWILIGHT END

Nautical

Civil

Rise

Set

Civil

Nautical

1

Monday

5:17

5:49

6:17

20:00

20:27

21:00

2

Tuesday

5:18

5:51

6:18

20:00

20:27

20:59

3

Wednesday

5:19

5:52

6:19

19:59

20:26

20:58

4

Thursday

5:20

5:53

6:20

19:58

20:25

20:57

5

Friday

5:21

5:54

6:21

19:57

20:24

20:56

6

Saturday

5:23

5:55

6:22

19:56

20:23

20:55

7

Sunday

5:24

5:56

6:23

19:56

20:22

20:54

8

Monday

5:25

5:57

6:24

19:55

20:21

20:53

9

Tuesday

5:26

5:58

6:24

19:54

20:20

20:52

10

Wednesday

5:27

5:59

6:25

19:53

20:19

20:51

11

Thursday

5:28

6:00

6:26

19:52

20:18

20:50

12

Friday

5:30

6:01

6:27

19:51

20:17

20:49

13

Saturday

5:31

6:02

6:28

19:50

20:16

20:47

14

Sunday

5:32

6:03

6:29

19:49

20:15

20:46

15

Monday

5:33

6:04

6:30

19:48

20:14

20:45

16

Tuesday

5:34

6:05

6:31

19:47

20:13

20:44

17

Wednesday

5:35

6:06

6:32

19:46

20:12

20:43

18

Thursday

5:36

6:07

6:33

19:45

20:11

20:41

19

Friday

5:37

6:08

6:34

19:44

20:09

20:40

20

Saturday

5:38

6:09

6:35

19:42

20:08

20:39

21

Sunday

5:39

6:10

6:36

19:41

20:07

20:38

22

Monday

5:40

6:11

6:37

19:40

20:06

20:36

23

Tuesday

5:41

6:12

6:38

19:39

20:05

20:35

24

Wednesday

5:42

6:13

6:38

19:38

20:03

20:34

25

Thursday

5:43

6:14

6:39

19:37

20:02

20:32

26

Friday

5:44

6:15

6:40

19:35

20:01

20:31

27

Saturday

5:45

6:16

6:41

19:34

20:00

20:30

28

Sunday

5:46

6:17

6:42

19:33

19:58

20:28

60

2021 AUSTRAL ASIAN SKY GUIDE

Moon and tides MOON

TIMES AND HEIGHTS OF HIGH AND LOW WATERS Time

H (m)

Date

Rise

Set

Time

H (m)

Time

H (m)

Time

H (m)

22:29

9:28

5:20

0.44

11:43

1.84

18:14

0.28

23:01 10:35

0:22

1.49

6:12

0.47

12:29

1.75

18:57

0.33

2

23:33 11:41

1:12

1.51

7:08

0.51

13:18

1.62

19:42

0.40

3

1

2:05

1.53

8:12

0.56

14:15

1.47

20:32

0.47

4

3:05

1.56

9:26

0.59

15:22

1.34

21:30

0.54

5

0:46 15:04

4:10

1.60

10:48

0.57

16:42

1.26

22:33

0.58

6

1:30 16:12

5:16

1.66

12:08

0.51

18:01

1.25

23:40

0.58

7

2:20 17:16

6:21

1.73

13:15

0.43

19:09

1.28

3:17 18:15

0:42

0.55

7:19

1.80

14:10

0.35

20:04

1.33

9

4:18 19:06

1:37

0.51

8:12

1.86

14:57

0.30

20:52

1.38

10

5:22 19:49

2:28

0.47

8:59

1.88

15:39

0.28

21:35

1.42

11

6:27 20:27

3:14

0.45

9:42

1.87

16:17

0.29

22:15

1.44

12

7:29 21:00

3:56

0.45

10:22

1.83

16:53

0.32

22:53

1.45

13

8:29 21:29

4:37

0.47

11:00

1.75

17:27

0.37

23:30

1.45

14

8

9:27 21:56

5:16

0.51

11:34

1.65

17:58

0.43

10:23 22:23

0:05

1.45

5:57

0.56

12:09

1.55

18:28

0.49

15 16

11:19 22:50

0:43

1.44

6:41

0.62

12:45

1.44

19:00

0.55

17

12:14 23:19

1:23

1.43

7:29

0.68

13:26

1.33

19:36

0.61

18

13:10 23:51

2:09

1.42

8:27

0.72

14:16

1.23

20:21

0.68

19

14:07

3:03

1.42

9:38

0.74

15:23

1.15

21:19

0.73

20

15:04

0:27

4:05

1.43

10:58

0.72

16:45

1.12

22:28

0.74

21

16:01

1:08

5:10

1.47

12:09

0.66

18:02

1.15

23:33

0.72

22

16:55

1:56

6:09

1.55

13:04

0.57

19:00

1.21

17:46

2:51

0:30

0.66

7:00

1.64

13:48

0.48

19:45

1.29

24

18:33

3:51

1:17

0.58

7:45

1.74

14:29

0.39

20:25

1.37

25

19:15

4:56

2:02

0.50

8:29

1.83

15:07

0.30

21:05

1.45

26

19:52

6:04

2:47

0.42

9:12

1.90

15:45

0.25

21:45

1.53

27

20:27

7:12

3:32

0.36

9:55

1.92

16:23

0.22

22:28

1.60

28

23

Tidal predictions for Sydney only. Times are adjusted for daylight saving. © Commonwealth of Australia, Bureau of Meteorology, National Tidal Centre.

2021 AUSTRAL ASIAN SKY GUIDE

61

FEB

12:48 0:08 13:56

MAR

KEY







Bright Star

Faint Star Magellanic Cloud



MARS M

This sky map shows the ZODIAC CONSTELLATIONS, Non-Zodiac Constellations and Stars of the night sky as seen from Sydney at: 9:30 pm on 7 March 8:30 pm on 21 March For other dates subtract or add half an hour each week.

62

2021 AUSTRAL ASIAN SKY GUIDE

MARCH 2021 The evening sky See sky map opposite The summer constellation of Orion is high in the north-west. Above and to the right or east is Sirius, the brightest star in the sky. Procyon is below Sirius and further below we find the two bright stars of Gemini, the Twins. Pollux is the star above, while Castor is closer to the horizon. Castor is a fascinating star as telescopes show it to be a triple star, with two bright components and a much fainter one. However, each of these three is also double so, in fact, Castor consists of six stars! The Southern Cross or Crux is lying on its side in the south-east, with the two pointer stars below. If we extend an imaginary line through the two topmost stars of the Cross to the right or west, we reach the bright star Canopus, high up and almost due south. Canopus is the second brightest star in the sky after Sirius and is the brightest star in the constellation of Carina, the Keel. Extending another imaginary line towards the right or west, this time through the main axis of the Cross, we reach the star Achernar, the brightest star in the constellation of Eridanus, the River.

Equinox The autumn equinox occurs when the Sun crosses from the southern to the northern part of the sky. It can take place on 20 or 21 March; this year it is the 20th. On the day of the equinox, the Sun rises close to due east and sets close to due west, while the length of daytime and night time are almost equal at 12 hours each. After the equinox, daytime length will decrease until the winter solstice.

DIARY FOR MARCH 2021

6

Saturday

Last quarter

12:30 pm

13

Saturday

New Moon

9:21 pm

20

Saturday

Autumn equinox

8:37 pm

22

Monday

First quarter

1:40 am

29

Monday

Full Moon

5:48 am

2021 AUSTRAL ASIAN SKY GUIDE

63

Evening twilight Mars is still the only evening planet. Mars is in the north-west in Taurus. On 19 March the crescent Moon is to the left or west of Mars, while the next evening the Moon is above and to the right or north of the planet.

Morning twilight Mercury is low in the east, starting the month in Capricornus and moving into Aquarius in the middle of the month. On 5 and 6 March it passes Jupiter at a separation of about one moon-width; Jupiter is the brighter of the two. Venus is very low in the east in Aquarius at the start of the month but disappears into the twilight within a few days. Jupiter is in the east in Capricornus, below Saturn. On 11 March the crescent Moon is below and to the right or south of Jupiter. Saturn is also in the east in Capricornus. On 10 March the crescent Moon is above and to the right or south of Saturn.

6:00 am on 11 March — three planets and the crescent Moon

64

2021 AUSTRAL ASIAN SKY GUIDE

Planets MERCURY Date

VENUS Set

MARS Rise

Set

JUPITER

SATURN

Set

Rise

Rise

Set

Rise

Set

4:37

18:12

6:12

19:19 12:59 23:03

4:48

18:24

4:09

17:57

2

4:37

18:11

6:14

19:19 12:57 23:01

4:46

18:20

4:06

17:54

3

4:36

18:11

6:16

19:18 12:56 22:59

4:43

18:17

4:02

17:50

4

4:36

18:10

6:18

19:18 12:55 22:58

4:40

18:14

3:59

17:47

5

4:36

18:10

6:20

19:17 12:54 22:56

4:37

18:11

3:55

17:43

6

4:37

18:09

6:22

19:17 12:53 22:54

4:34

18:07

3:52

17:39

7

4:37

18:09

6:24

19:16 12:52 22:52

4:31

18:04

3:48

17:36

8

4:38

18:09

6:27

19:15 12:51 22:50

4:28

18:01

3:45

17:32

9

4:39

18:09

6:29

19:15 12:50 22:48

4:26

17:58

3:42

17:29

10

4:41

18:09

6:31

19:14 12:49 22:46

4:23

17:54

3:38

17:25

11

4:42

18:09

6:33

19:14 12:48 22:45

4:20

17:51

3:35

17:21

12

4:44

18:09

6:35

19:13 12:46 22:43

4:17

17:48

3:31

17:18

13

4:46

18:09

6:37

19:12 12:45 22:41

4:14

17:45

3:28

17:14

14

4:48

18:09

6:39

19:12 12:44 22:39

4:11

17:41

3:24

17:11

15

4:50

18:10

6:41

19:11 12:43 22:37

4:08

17:38

3:21

17:07

16

4:52

18:10

6:43

19:10 12:42 22:36

4:05

17:35

3:17

17:03

17

4:54

18:10

6:45

19:09 12:41 22:34

4:03

17:32

3:14

17:00

18

4:57

18:10

6:47

19:09 12:40 22:32

4:00

17:28

3:10

16:56

19

5:00

18:11

6:49

19:08 12:39 22:30

3:57

17:25

3:07

16:52

20

5:02

18:11

6:51

19:07 12:38 22:29

3:54

17:22

3:03

16:49

21

5:05

18:11

6:52

19:07 12:37 22:27

3:51

17:18

3:00

16:45

22

5:08

18:11

6:54

19:06 12:36 22:25

3:48

17:15

2:56

16:42

23

5:12

18:12

6:56

19:05 12:34 22:24

3:45

17:12

2:53

16:38

24

5:15

18:12

6:58

19:04 12:33 22:22

3:42

17:08

2:49

16:34

25

5:18

18:12

7:00

19:04 12:32 22:21

3:39

17:05

2:46

16:31

26

5:22

18:13

7:02

19:03 12:31 22:19

3:36

17:02

2:42

16:27

27

5:25

18:13

7:04

19:02 12:30 22:17

3:33

16:58

2:39

16:23

28

5:29

18:13

7:06

19:01 12:29 22:16

3:30

16:55

2:35

16:20

29

5:33

18:14

7:08

19:01 12:28 22:14

3:27

16:52

2:32

16:16

30

5:37

18:14

7:10

19:00 12:27 22:13

3:24

16:48

2:28

16:12

31

5:41

18:14

7:12

18:59 12:26 22:11

3:21

16:45

2:25

16:09

2021 AUSTRAL ASIAN SKY GUIDE

65

MAR

Rise

1

Sun and twilight TWILIGHT START

MAR

Date

Day

SUN

TWILIGHT END

Nautical

Civil

Rise

Set

Civil

Nautical

1

Monday

5:47

6:17

6:43

19:32

19:57

20:27

2

Tuesday

5:48

6:18

6:44

19:30

19:56

20:26

3

Wednesday

5:49

6:19

6:45

19:29

19:54

20:24

4

Thursday

5:50

6:20

6:45

19:28

19:53

20:23

5

Friday

5:51

6:21

6:46

19:27

19:52

20:22

6

Saturday

5:52

6:22

6:47

19:25

19:51

20:20

7

Sunday

5:53

6:23

6:48

19:24

19:49

20:19

8

Monday

5:54

6:24

6:49

19:23

19:48

20:17

9

Tuesday

5:55

6:24

6:50

19:21

19:47

20:16

10

Wednesday

5:56

6:25

6:50

19:20

19:45

20:15

11

Thursday

5:57

6:26

6:51

19:19

19:44

20:13

12

Friday

5:57

6:27

6:52

19:17

19:43

20:12

13

Saturday

5:58

6:28

6:53

19:16

19:41

20:10

14

Sunday

5:59

6:29

6:54

19:15

19:40

20:09

15

Monday

6:00

6:29

6:54

19:13

19:38

20:08

16

Tuesday

6:01

6:30

6:55

19:12

19:37

20:06

17

Wednesday

6:02

6:31

6:56

19:11

19:36

20:05

18

Thursday

6:03

6:32

6:57

19:09

19:34

20:03

19

Friday

6:03

6:32

6:57

19:08

19:33

20:02

20

Saturday

6:04

6:33

6:58

19:07

19:32

20:01

21

Sunday

6:05

6:34

6:59

19:05

19:30

19:59

22

Monday

6:06

6:35

7:00

19:04

19:29

19:58

23

Tuesday

6:07

6:36

7:00

19:03

19:28

19:57

24

Wednesday

6:07

6:36

7:01

19:01

19:26

19:55

25

Thursday

6:08

6:37

7:02

19:00

19:25

19:54

26

Friday

6:09

6:38

7:03

18:59

19:23

19:52

27

Saturday

6:10

6:39

7:03

18:57

19:22

19:51

28

Sunday

6:10

6:39

7:04

18:56

19:21

19:50

29

Monday

6:11

6:40

7:05

18:55

19:19

19:48

30

Tuesday

6:12

6:41

7:06

18:53

19:18

19:47

31

Wednesday

6:13

6:42

7:06

18:52

19:17

19:46

66

2021 AUSTRAL ASIAN SKY GUIDE

Moon and tides MOON

TIMES AND HEIGHTS OF HIGH AND LOW WATERS

Rise

Set

Time

H (m)

Time

H (m)

Time

H (m)

Time

H (m)

Date

21:00

8:20

4:20

0.33

10:40

1.89

17:03

0.23

23:11

1.65

1

21:33

23:57

1.68

2

9:29

5:11

0.34

11:26

1.81

17:44

0.28

22:08 10:38

6:04

0.37

12:15

1.68

18:26

0.36

22:46 11:47

0:45

1.68

7:02

0.43

13:07

1.53

19:11

0.46

4

23:28 12:57

1:39

1.67

8:08

0.50

14:06

1.37

20:01

0.57

5

3

2:39

1.64

9:24

0.55

15:19

1.25

21:04

0.65

6

3:48

1.63

10:47

0.55

16:45

1.20

22:19

0.70

7

1:10 16:10

5:03

1.64

12:03

0.51

18:05

1.23

23:33

0.68

8

2:10 17:03

6:11

1.68

13:05

0.45

19:06

1.30

3:12 17:48

0:38

0.62

7:09

1.73

13:54

0.40

19:54

1.38

10

4:15 18:26

1:32

0.55

7:58

1.77

14:35

0.36

20:35

1.44

11

5:18 19:00

2:19

0.50

8:41

1.78

15:12

0.35

21:13

1.50

12

6:18 19:30

3:00

0.47

9:20

1.76

15:45

0.36

21:47

1.53

13

7:16 19:57

3:39

0.46

9:57

1.71

16:15

0.39

22:20

1.56

14

8:13 20:24

4:17

0.47

10:30

1.65

16:44

0.43

22:53

1.57

15

9:09 20:51

4:55

0.50

11:04

1.57

17:12

0.48

23:25

1.58

16

10:05 21:19

5:33

0.53

11:39

1.48

17:40

0.53

23:59

1.57

17

11:01 21:49

6:15

0.58

12:15

1.39

18:09

0.60

11:57 22:23

0:35

1.55

7:00

0.63

12:57

1.30

18:44

0.67

19

12:54 23:02

1:17

1.52

7:54

0.68

13:45

1.21

19:26

0.74

20

13:50 23:46

2:08

1.48

9:00

0.71

14:49

1.15

20:24

0.80

21

14:45

9

18

3:11

1.46

10:15

0.71

16:12

1.13

21:40

0.82

22

15:37

0:37

4:22

1.48

11:27

0.66

17:32

1.17

22:57

0.79

23

16:24

1:34

5:30

1.54

12:24

0.57

18:30

1.26

17:07

2:36

0:00

0.71

6:25

1.64

13:10

0.47

19:15

1.36

25

17:46

3:41

0:53

0.60

7:14

1.74

13:51

0.38

19:56

1.48

26

18:22

4:49

1:42

0.49

8:00

1.83

14:30

0.30

20:37

1.59

27

18:56

5:58

2:30

0.39

8:45

1.88

15:10

0.25

21:18

1.70

28

19:29

7:08

3:18

0.32

9:32

1.88

15:50

0.24

22:01

1.79

29

20:04

8:18

4:08

0.28

10:20

1.82

16:30

0.27

22:46

1.85

30

20:41

9:30

5:01

0.28

11:11

1.72

17:13

0.35

23:33

1.87

31

24

Tidal predictions for Sydney only. Times are adjusted for daylight saving. © Commonwealth of Australia, Bureau of Meteorology, National Tidal Centre.

2021 AUSTRAL ASIAN SKY GUIDE

67

MAR

14:06 0:16 15:11

APR

KEY







Bright Star

Faint Star Magellanic Cloud



MARS M

This sky map shows the ZODIAC CONSTELLATIONS, Non-Zodiac Constellations and Stars of the night sky as seen from Sydney at: 7:30 pm on 7 April 6:30 pm on 21 April For other dates subtract or add half an hour each week.

68

2021 AUSTRAL ASIAN SKY GUIDE

APRIL 2021 The evening sky See sky map opposite The summer constellation of Orion is lying on its side in the western sky. Sirius, the brightest star in the sky, is above and to the left or south of Orion. Procyon, the brightest star in the constellation of Canis Minor, the Little Dog, is above and to the right or north. In the east we can see Spica, the brightest star in the constellation of Virgo, the Maiden. Spica consists of two hot massive stars whirling around each other every four days. In the south the Southern Cross is straightening up and is now at about the four o’clock angle. The first of the two pointers below is Beta Centauri, also known as Hadar, which is a hot giant star about 390 light years from us. The second pointer is Alpha Centauri or Rigel Kentaurus. With a small telescope you can see it as a pair of bright stars close together — one of the best sights in the southern sky. A third star in the Alpha Centauri system, called Proxima Centauri, is the closest star to the Sun at a distance of 4.3 light years. Proxima also hosts the closest known exoplanet, which circles around it every 11.2 days. The two pointer stars are part of the constellation of Centaurus, the Centaur, which borders the Southern Cross on three sides. In Greek mythology centaurs were half-horse and half-human creatures. Canopus, the second brightest star in the sky and the brightest star in the constellation of Carina, the Keel, is high in the south.

DIARY FOR APRIL 2021

4

Summer time ends

3:00 am



Sunday

Last quarter

8:02 pm

12

Monday

New Moon

12:31 pm

20

Tuesday

First quarter

4:59 pm

27

Tuesday

Full Moon

1:32 pm

2021 AUSTRAL ASIAN SKY GUIDE

69

Evening twilight At the end of the month Mars is joined by Venus in the evening sky. Venus appears low in the west in Aries in the middle of the last week of the month. Mars is in the north-west in Taurus at the beginning of the month but moves into Gemini at the beginning of the last week of the month. On 17 April the crescent Moon is below and to the left or west of the planet.

Morning twilight Mercury is very low in the east in Aquarius at the start of the month. Within three days it has moved into Pisces and early in the second week of the month it has disappeared into the twilight. Jupiter is in the east, starting the month in Capricornus but moving into Aquarius in the middle of the last week. On 7 April the crescent Moon is above and to the right or south of Jupiter, while the next morning it is below and again to the right or south of the planet. Saturn is in the east in Capricornus. On 6 April the crescent Moon is above and to the right or south of Saturn.

5:15 am on 7 April — three planets and the crescent Moon

70

2021 AUSTRAL ASIAN SKY GUIDE

Planets MERCURY Date

VENUS Set

MARS Rise

Set

JUPITER

SATURN

Rise

Set

Rise

Rise

Set

1

5:45

18:15

7:14

18:58 12:24 22:09

3:18

16:42

Rise

2:21 16:05

Set

2

5:49

18:15

7:16

18:58 12:23 22:08

3:15

16:38

2:18 16:01

3

5:54

18:16

7:18

18:57 12:22 22:06

3:12

16:35

2:14 15:58

4

4:58

17:16

6:20

17:56 11:21 21:05

2:09

15:32

2:11 14:54

5

5:03

17:17

6:22

17:55 11:20 21:03

2:06

15:28

1:07 14:50

6

5:07

17:17

6:24

17:55 11:19 21:02

2:03

15:25

1:03 14:47

7

5:12

17:18

6:26

17:54 11:18 21:01

2:00

15:22

1:00 14:43

8

5:17

17:19

6:28

17:53 11:16 20:59

1:57

15:18

0:56 14:39

5:22

17:19

6:30

17:53 11:15 20:58

1:54

15:15

0:53 14:35

5:27

17:20

6:32

17:52 11:14 20:56

1:51

15:11

0:49 14:32

11

5:33

17:21

6:34

17:52 11:13 20:55

1:48

15:08

0:45 14:28

12

5:38

17:22

6:36

17:51 11:12 20:53

1:45

15:05

0:42 14:24

13

5:44

17:22

6:38

17:50 11:11 20:52

1:42

15:01

0:38 14:21

14

5:50

17:23

6:40

17:50 11:09 20:51

1:39

14:58

0:34 14:17

15

5:55

17:24

6:42

17:49 11:08 20:49

1:36

14:54

0:31 14:13

16

6:01

17:26

6:44

17:49 11:07 20:48

1:33

14:51

0:27 14:09

17

6:07

17:27

6:46

17:48 11:06 20:47

1:30

14:48

0:24 14:06

18

6:14

17:28

6:48

17:48 11:04 20:45

1:27

14:44

0:20 14:02

19

6:20

17:29

6:50

17:47 11:03 20:44

1:23

14:41

0:16 13:58

20

6:26

17:31

6:52

17:47 11:02 20:43

1:20

14:37

0:13 13:54

21

6:33

17:32

6:54

17:46 11:01 20:41

1:17

14:34

0:09 13:51

22

6:39

17:34

6:56

17:46 10:59 20:40

1:14

14:30

0:05 13:47

23

6:46

17:35

6:58

17:46 10:58 20:39

1:11

14:27

0:01 13:43

24

6:53

17:37

7:00

17:45 10:57 20:38

1:08

14:23 23:54 13:39

25

6:59

17:39

7:02

17:45 10:56 20:36

1:05

14:20 23:50 13:35

26

7:06

17:41

7:04

17:45 10:54 20:35

1:01

14:16 23:47 13:32

27

7:13

17:43

7:07

17:44 10:53 20:34

0:58

14:13 23:43 13:28

28

7:19

17:45

7:09

17:44 10:52 20:33

0:55

14:09 23:39 13:24

29

7:26

17:46

7:11

17:44 10:50 20:31

0:52

14:06 23:35 13:20

30

7:32

17:48

7:13

17:44 10:49 20:30

0:48

14:02 23:32 13:17

23:58

2021 AUSTRAL ASIAN SKY GUIDE

71

APR

9 10

Sun and twilight TWILIGHT START

APR

Date

Day

SUN

TWILIGHT END

Nautical

Civil

Rise

Set

Civil

Nautical

1

Thursday

6:13

6:42

7:07

18:51

19:15

19:44

2

Friday

6:14

6:43

7:08

18:49

19:14

19:43

3

Saturday

6:15

6:44

7:09

18:48

19:13

19:42

4

Sunday

5:16

5:44

6:09

17:47

18:11

18:40

5

Monday

5:16

5:45

6:10

17:45

18:10

18:39

6

Tuesday

5:17

5:46

6:11

17:44

18:09

18:38

7

Wednesday

5:18

5:47

6:12

17:43

18:08

18:37

8

Thursday

5:18

5:47

6:12

17:41

18:06

18:35

9

Friday

5:19

5:48

6:13

17:40

18:05

18:34

10

Saturday

5:20

5:49

6:14

17:39

18:04

18:33

11

Sunday

5:21

5:50

6:15

17:37

18:03

18:32

12

Monday

5:21

5:50

6:15

17:36

18:01

18:30

13

Tuesday

5:22

5:51

6:16

17:35

18:00

18:29

14

Wednesday

5:23

5:52

6:17

17:34

17:59

18:28

15

Thursday

5:23

5:52

6:18

17:32

17:58

18:27

16

Friday

5:24

5:53

6:18

17:31

17:57

18:26

17

Saturday

5:25

5:54

6:19

17:30

17:55

18:24

18

Sunday

5:25

5:55

6:20

17:29

17:54

18:23

19

Monday

5:26

5:55

6:21

17:28

17:53

18:22

20

Tuesday

5:27

5:56

6:21

17:26

17:52

18:21

21

Wednesday

5:27

5:57

6:22

17:25

17:51

18:20

22

Thursday

5:28

5:57

6:23

17:24

17:50

18:19

23

Friday

5:29

5:58

6:24

17:23

17:49

18:18

24

Saturday

5:29

5:59

6:24

17:22

17:48

18:17

25

Sunday

5:30

6:00

6:25

17:21

17:46

18:16

26

Monday

5:31

6:00

6:26

17:20

17:45

18:15

27

Tuesday

5:32

6:01

6:27

17:19

17:44

18:14

28

Wednesday

5:32

6:02

6:27

17:18

17:43

18:13

29

Thursday

5:33

6:02

6:28

17:17

17:42

18:12

30

Friday

5:34

6:03

6:29

17:16

17:41

18:11

72

2021 AUSTRAL ASIAN SKY GUIDE

Moon and tides MOON Rise

TIMES AND HEIGHTS OF HIGH AND LOW WATERS

Set

Time

H (m)

Date

Time

H (m)

Time

H (m)

Time

H (m)

21:23 10:43

5:58

0.32

12:03

1.58

17:57

0.45

22:11 11:55

0:22

1.85

6:59

0.38

13:00

1.44

18:45

0.57

2

23:04 13:04

1:16

1.79

8:06

0.46

14:05

1.31

19:40

0.68

3

23:03 13:06

2:18

1.72

8:22

0.51

14:22

1.24

19:48

0.75

4

14:01

2:31

1.66

9:38

0.53

15:46

1.24

21:09

0.78

5

0:06 14:48

3:47

1.63

10:45

0.52

16:55

1.29

22:25

0.74

6

1:09 15:28

4:54

1.64

11:40

0.49

17:48

1.37

23:29

0.68

7

2:11 16:02

5:48

1.66

12:25

0.46

18:31

1.45

3:11 16:33

0:21

0.61

6:34

1.67

13:02

0.45

19:09

1.53

9

4:09 17:01

1:05

0.56

7:15

1.66

13:35

0.44

19:44

1.59

10

5:06 17:27

1:45

0.52

7:52

1.63

14:04

0.45

20:16

1.63

11

6:02 17:53

2:21

0.50

8:27

1.59

14:32

0.47

20:47

1.67

12

6:57 18:21

2:58

0.50

9:01

1.54

15:00

0.51

21:18

1.70

13

7:53 18:50

3:34

0.50

9:37

1.48

15:28

0.55

21:49

1.71

14

8:50 19:22

4:13

0.52

10:14

1.42

15:57

0.61

22:23

1.70

15

9:46 19:59

4:54

0.56

10:52

1.35

16:29

0.67

22:59

1.67

16

10:43 20:41

5:38

0.60

11:35

1.28

17:05

0.73

23:40

1.62

17

11:38 21:28

6:29

0.65

12:25

1.22

17:49

0.79

12:30 22:22

0:28

1.57

7:29

0.68

13:25

1.18

18:46

0.84

19

13:18 23:21

1:28

1.54

8:36

0.68

14:39

1.19

20:00

0.86

20

14:02

2:37

1.54

9:42

0.63

15:53

1.24

21:18

0.82

21

1

8

14:41

0:23

3:45

1.58

10:37

0.55

16:51

1.34

22:27

0.74

22

15:17

1:28

4:45

1.66

11:25

0.46

17:38

1.47

23:26

0.62

23

15:51

2:35

5:39

1.73

12:08

0.38

18:22

1.61

16:24

3:43

0:19

0.50

6:29

1.79

12:50

0.32

19:06

1.75

25

16:57

4:53

1:12

0.39

7:19

1.80

13:32

0.30

19:50

1.87

26

17:33

6:05

2:04

0.31

8:10

1.77

14:15

0.31

20:35

1.97

27

18:14

7:18

2:58

0.26

9:02

1.70

14:59

0.36

21:23

2.02

28

19:00

8:33

3:53

0.26

9:58

1.60

15:44

0.45

22:12

2.02

29

19:53

9:47

4:51

0.29

10:54

1.49

16:32

0.55

23:03

1.97

30

24

Tidal predictions for Sydney only. Times are adjusted for daylight saving. © Commonwealth of Australia, Bureau of Meteorology, National Tidal Centre.

2021 AUSTRAL ASIAN SKY GUIDE

73

APR

18

M AY

KEY







Bright Star

Faint Star Magellanic Cloud



M2 MERCURY ON 21 MAY M V2 VENUS ON 21 MAY

M MARS

74

2021 AUSTRAL ASIAN SKY GUIDE

This sky map shows the ZODIAC CONSTELLATIONS, Non-Zodiac Constellations and Stars of the night sky as seen from Sydney at: 6:30 pm on 7 May 5:30 pm on 21 May For other dates subtract or add half an hour each week.

MAY 2021 The evening sky See sky map opposite The summer constellation of Orion is lying on its side low in the western sky. Above and to the left or south is the brightest star in the sky, Sirius, while above and to the right or north is Procyon. Further north we see Pollux and Castor, the twin stars of Gemini. Due north is Regulus, the brightest star in the constellation of Leo, the Lion. Regulus lies on the ecliptic, the line traced out by the planets, the Sun and the Moon in their journeys around the sky. Hence Regulus is often occulted, or covered, by the Moon. Low in the east we have the welcome return of the favourite constellation of the Australian winter sky, Scorpius, the Scorpion. It is easily recognisable, consisting of a line of bright stars, including the bright red star Antares. Scorpius rises as Orion is setting, recalling the ancient Greek story of the Scorpion chasing the giant Orion.

Total eclipse of the Moon On the evening of Wednesday 26 May the Moon moves into the shadow of the Earth. Lasting just over three hours, this spectacular event is visible throughout Australia and New Zealand (see page 9).

Meteor shower The Eta Aquariids occur this month. Associated with Halley’s Comet, this meteor shower is one of the best to be seen from the southern hemisphere. Look for meteors in the eastern sky in the early mornings of Thursday 6 May and Friday 7 May. The waning crescent Moon is in the sky but should not cause too many problems, especially on the second morning (see page 7).

D I A R Y F O R M AY 2 0 2 1

4

Tuesday

Last quarter

5:50 am

12

Wednesday

New Moon

5:00 am

20

Thursday

First quarter

5:13 am

26

Wednesday

Full Moon

9:14 pm

2021 AUSTRAL ASIAN SKY GUIDE

75

Evening twilight Mars is accompanied by Venus and, for most of the month, Mercury. Mercury appears low in the north-west in Taurus in the middle of the second week of the month. It disappears into the twilight at the very end of the month. On 14 May a thin crescent Moon is above and to the right or north of the planet. On 29 May Mercury, on its way down towards the horizon, passes Venus, on its way up, at a separation of just under one moon-width. Venus is very low in the north-west, moving from Aries into Taurus in the middle of the first week of the month. On 13 May a very thin crescent Moon maybe just visible above and to the right or north of Venus. Mars is in the north-west in Gemini. On 16 May the crescent Moon is below and to the right or north of Mars.

Morning twilight Jupiter is high in the north-east in Aquarius. On 5 May the crescent Moon is above and to the right or east of Jupiter. Saturn is high in the north in Capricornus. On 4 May the last quarter Moon is above and to the right or east of Saturn. On 31 May the gibbous Moon is to the left or west of Saturn. 5:45 pm on 13 May — two planets and the crescent Moon

76

2021 AUSTRAL ASIAN SKY GUIDE

Planets MERCURY Date

VENUS Set

MARS Rise

Set

JUPITER Rise

Set

SATURN

Rise

Set

Rise

1

7:38

17:50

7:15

17:44 10:48 20:29

0:45 13:59 23:28 13:13

Rise

Set

2

7:44

17:52

7:17

17:44 10:46 20:28

0:42 13:55 23:24 13:09

3

7:49

17:54

7:19

17:44 10:45 20:27

0:39 13:52 23:20 13:05

4

7:55

17:56

7:21

17:44 10:44 20:26

0:35 13:48 23:17 13:01

5

8:00

17:58

7:23

17:44 10:42 20:24

0:32 13:45 23:13 12:57

6

8:05

18:00

7:25

17:44 10:41 20:23

0:29 13:41 23:09 12:54

7

8:09

18:02

7:27

17:44 10:40 20:22

0:26 13:38 23:05 12:50

8

8:13

18:04

7:30

17:44 10:38 20:21

0:22 13:34 23:01 12:46

8:17

18:05

7:32

17:44 10:37 20:20

0:19 13:31 22:58 12:42

8:21

18:07

7:34

17:44 10:35 20:19

0:16 13:27 22:54 12:38

11

8:24

18:08

7:36

17:45 10:34 20:18

0:12 13:23 22:50 12:34

12

8:26

18:09

7:38

17:45 10:32 20:17

0:09 13:20 22:46 12:31

13

8:29

18:10

7:40

17:45 10:31 20:16

0:05 13:16 22:42 12:27

14

8:31

18:11

7:42

17:46 10:29 20:14

0:02 13:13 22:38 12:23

15

8:32

18:12

7:44

17:46 10:28 20:13 23:55 13:09 22:34 12:19

16

8:33

18:13

7:46

17:47 10:26 20:12 23:52 13:05 22:31 12:15

17

8:34

18:13

7:48

17:47 10:25 20:11 23:48 13:02 22:27 12:11

18

8:34

18:13

7:50

17:48 10:23 20:10 23:45 12:58 22:23 12:07

19

8:34

18:13

7:52

17:49 10:22 20:09 23:41 12:55 22:19 12:03

20

8:34

18:13

7:54

17:49 10:20 20:08 23:38 12:51 22:15 11:59

21

8:33

18:12

7:56

17:50 10:19 20:07 23:34 12:47 22:11 11:56

22

8:32

18:11

7:58

17:51 10:17 20:06 23:31 12:44 22:07 11:52

23

8:30

18:10

8:00

17:52 10:16 20:05 23:27 12:40 22:03 11:48

24

8:28

18:09

8:02

17:52 10:14 20:04 23:24 12:36 21:59 11:44

25

8:25

18:08

8:03

17:53 10:13 20:03 23:20 12:33 21:55 11:40

26

8:22

18:06

8:05

17:54 10:11 20:02 23:17 12:29 21:51 11:36

27

8:19

18:04

8:07

17:55 10:09 20:01 23:13 12:25 21:47 11:32

28

8:15

18:01

8:09

17:56 10:08 20:00 23:10 12:21 21:43 11:28

29

8:11

17:58

8:10

17:57 10:06 19:59 23:06 12:18 21:39 11:24

30

8:06

17:55

8:12

17:59 10:04 19:58 23:02 12:14 21:35 11:20

31

8:01

17:52

8:14

18:00 10:03 19:57 22:59 12:10 21:31 11:16

23:59

2021 AUSTRAL ASIAN SKY GUIDE

77

M AY

9 10

Sun and twilight TWILIGHT START

M AY

Date

Day

SUN

TWILIGHT END

Nautical

Civil

Rise

Set

Civil

Nautical

1

Saturday

5:34

6:04

6:30

17:15

17:40

18:10

2

Sunday

5:35

6:04

6:30

17:14

17:40

18:09

3

Monday

5:36

6:05

6:31

17:13

17:39

18:08

4

Tuesday

5:36

6:06

6:32

17:12

17:38

18:07

5

Wednesday

5:37

6:07

6:33

17:11

17:37

18:07

6

Thursday

5:38

6:07

6:33

17:10

17:36

18:06

7

Friday

5:38

6:08

6:34

17:09

17:35

18:05

8

Saturday

5:39

6:09

6:35

17:08

17:34

18:04

9

Sunday

5:39

6:09

6:36

17:07

17:34

18:03

10

Monday

5:40

6:10

6:36

17:06

17:33

18:03

11

Tuesday

5:41

6:11

6:37

17:06

17:32

18:02

12

Wednesday

5:41

6:11

6:38

17:05

17:31

18:01

13

Thursday

5:42

6:12

6:39

17:04

17:31

18:01

14

Friday

5:43

6:13

6:39

17:03

17:30

18:00

15

Saturday

5:43

6:14

6:40

17:03

17:29

17:59

16

Sunday

5:44

6:14

6:41

17:02

17:29

17:59

17

Monday

5:45

6:15

6:42

17:01

17:28

17:58

18

Tuesday

5:45

6:16

6:42

17:01

17:27

17:58

19

Wednesday

5:46

6:16

6:43

17:00

17:27

17:57

20

Thursday

5:46

6:17

6:44

16:59

17:26

17:57

21

Friday

5:47

6:18

6:44

16:59

17:26

17:56

22

Saturday

5:48

6:18

6:45

16:58

17:25

17:56

23

Sunday

5:48

6:19

6:46

16:58

17:25

17:55

24

Monday

5:49

6:19

6:47

16:57

17:24

17:55

25

Tuesday

5:49

6:20

6:47

16:57

17:24

17:55

26

Wednesday

5:50

6:21

6:48

16:56

17:24

17:54

27

Thursday

5:51

6:21

6:48

16:56

17:23

17:54

28

Friday

5:51

6:22

6:49

16:56

17:23

17:54

29

Saturday

5:52

6:22

6:50

16:55

17:22

17:53

30

Sunday

5:52

6:23

6:50

16:55

17:22

17:53

31

Monday

5:53

6:24

6:51

16:55

17:22

17:53

78

2021 AUSTRAL ASIAN SKY GUIDE

Moon and tides MOON

TIMES AND HEIGHTS OF HIGH AND LOW WATERS Time

H (m)

Time

H (m)

Time

H (m)

Time

H (m)

Date

20:52 10:55

5:54

0.36

11:55

1.39

17:25

0.65

23:59

1.88

1

21:55 11:56

7:00

0.43

13:00

1.31

18:25

0.74

23:00 12:47

1:00

1.77

8:09

0.49

14:14

1.28

19:34

0.80

3

Rise

Set

2

13:30

2:09

1.68

9:14

0.53

15:25

1.30

20:50

0.82

4

0:04 14:06

3:20

1.62

10:12

0.55

16:26

1.36

22:03

0.79

5

1:05 14:37

4:23

1.59

11:00

0.55

17:16

1.44

23:07

0.74

6

2:04 15:05

5:16

1.57

11:42

0.54

17:59

1.52

3:01 15:32

0:00

0.68

6:01

1.55

12:17

0.53

18:36

1.59

3:56 15:58

0:45

0.63

6:42

1.53

12:49

0.53

19:11

1.66

9

4:52 16:24

1:25

0.58

7:19

1.51

13:20

0.54

19:43

1.71

10

5:47 16:53

2:02

0.55

7:57

1.48

13:49

0.56

20:15

1.76

11

6:43 17:24

2:39

0.52

8:34

1.44

14:19

0.58

20:46

1.78

12

7:40 17:59

3:16

0.51

9:13

1.41

14:50

0.62

21:19

1.79

13

8:37 18:39

3:55

0.52

9:52

1.37

15:24

0.66

21:55

1.78

14

7 8

4:35

0.54

10:33

1.32

16:00

0.71

22:32

1.75

15

5:19

0.58

11:17

1.28

16:40

0.75

23:14

1.71

16

11:15 21:12

6:08

0.61

12:07

1.25

17:26

0.80

11:59 22:12

0:00

1.66

7:02

0.62

13:03

1.24

18:22

0.83

18

12:39 23:15

0:56

1.62

8:00

0.61

14:07

1.26

19:29

0.84

19

13:15

1:58

1.61

8:58

0.58

15:12

1.33

20:43

0.81

20

17

13:48

0:18

3:04

1.62

9:50

0.52

16:09

1.44

21:54

0.74

21

14:20

1:24

4:07

1.65

10:39

0.45

17:00

1.57

22:59

0.63

22

14:52

2:30

5:05

1.67

11:25

0.40

17:48

1.72

15:26

3:39

0:00

0.51

6:00

1.68

12:10

0.37

18:36

1.86

24

16:03

4:51

0:57

0.40

6:56

1.67

12:56

0.37

19:24

1.98

25

16:46

6:05

1:53

0.31

7:51

1.63

13:43

0.40

20:13

2.06

26

17:36

7:21

2:49

0.26

8:48

1.57

14:30

0.45

21:02

2.10

27

18:34

8:34

3:45

0.25

9:45

1.50

15:21

0.51

21:54

2.08

28

19:38

9:40

4:43

0.28

10:44

1.43

16:14

0.59

22:46

2.01

29

20:45 10:38

5:42

0.34

11:43

1.38

17:09

0.66

23:41

1.91

30

21:52 11:26

6:42

0.42

12:44

1.34

18:07

0.73

23

31

Tidal predictions for Sydney only.

© Commonwealth of Australia, Bureau of Meteorology, National Tidal Centre.

2021 AUSTRAL ASIAN SKY GUIDE

79

M AY

9:33 19:24 10:26 20:16

JUN

KEY







Bright Star

Faint Star Magellanic Cloud



V2 VENUS ON 21 JUNE MARS M

This sky map shows the ZODIAC CONSTELLATIONS, Non-Zodiac Constellations and Stars of the night sky as seen from Sydney at: 6:30 pm on 7 June 5:30 pm on 21 June For other dates subtract or add half an hour each week.

80

2021 AUSTRAL ASIAN SKY GUIDE

JUNE 2021 The evening sky See sky map opposite The signpost to the winter sky, the constellation of Scorpius, the Scorpion, is prominent in the east. With its head or claws to the left or north and its tail to the right or south, it is one of the few constellations that has a resemblance to its name. The Scorpion even has a red heart, the star Antares. This is a red giant star at a distance of 550 light years from us and a width that is about four times that of the Earth’s path around the Sun. Further to the north we see the bright star Spica, the brightest star in the constellation of Virgo, high in the north-east. Below is the brilliant orange-coloured Arcturus in the constellation of Boötes. This star, at a distance of 37 light years from us, has an exceptionally low concentration of elements other than hydrogen and helium. In the north-east we reach Regulus, the brightest star in the constellation of Leo, the Lion, named after the Latin word meaning ‘Little King’, as it was once considered the ruler of the heavens. A very hot star at a distance of 79 light years from us, it has a flattened and distorted shape due to a very rapid spin around its axis. Above Regulus stretching across the sky is the constellation of Hydra, the Female Water Snake. This ancient constellation is the largest of the 88 constellations accepted by modern astronomers. The Southern Cross or Crux is at its highest and standing vertically in the south. Its brightest star, Acrux, is the one closest to the horizon, while the highest star is the red giant Gamma Crucis. DIARY FOR JUNE 2021

2

Wednesday

Last quarter

5:24 pm

10

Thursday

New Moon

8:53 pm

18

Friday

First quarter

1:54 pm

21

Monday

Winter solstice

1:32 pm

25

Friday

Full Moon

4:40 am

2021 AUSTRAL ASIAN SKY GUIDE

81

Evening twilight Venus and Mars are the evening planets. Venus is low in the north-west. It starts the month in Taurus, after two days moves into Gemini and near the end of the month moves to join Mars in Cancer. On 12 June a very thin crescent Moon is below and to the right or north of Venus. Mars is in the north-west, moving from Gemini into Cancer early in the second week of the month. On 13 June the crescent Moon is below and to the left or west of Mars, while the next evening it is above and to the right or north of the planet.

Morning twilight Mercury appears low in the east in Taurus just after the middle of the month. Jupiter is high in the north-west in Aquarius. On 1 June the gibbous Moon is above and to the left or west of Jupiter, while the next morning the Moon, now at first quarter, is above and to the right or north of the planet. The gibbous Moon is back on 29 June, this time above and to the left or west of the planet. Saturn is in the west in Capricornus. On 27 June the gibbous Moon is below and to the left or south of Jupiter, while on the next morning it is above the planet. 6:00 pm on 13 June — two planets and the crescent Moon

82

2021 AUSTRAL ASIAN SKY GUIDE

Planets MERCURY Date

VENUS Set

MARS Rise

Set

JUPITER Rise

Set

SATURN

Rise

Set

Rise

1

7:56

17:49

8:15

18:01 10:01 19:56 22:55 12:07 21:27 11:12

Rise

Set

2

7:51

17:45

8:17

18:02

9:59 19:55 22:52 12:03 21:23 11:08

3

7:45

17:41

8:19

18:04

9:58 19:54 22:48 11:59 21:19 11:04

4

7:39

17:36

8:20

18:05

9:56 19:53 22:44 11:55 21:15 11:00

5

7:32

17:32

8:22

18:06

9:54 19:52 22:40 11:52 21:11 10:56

6

7:26

17:27

8:23

18:08

9:53 19:51 22:37 11:48 21:07 10:52

7

7:19

17:22

8:24

18:09

9:51 19:51 22:33 11:44 21:03 10:48

8

7:12

17:17

8:26

18:11

9:49 19:50 22:29 11:40 20:59 10:44

7:05

17:12

8:27

18:12

9:47 19:49 22:26 11:36 20:55 10:40

6:58

17:06

8:28

18:14

9:46 19:48 22:22 11:33 20:51 10:36

11

6:51

17:01

8:29

18:16

9:44 19:47 22:18 11:29 20:47 10:32

12

6:43

16:56

8:31

18:17

9:42 19:46 22:14 11:25 20:43 10:28

13

6:37

16:50

8:32

18:19

9:40 19:45 22:10 11:21 20:39 10:24

14

6:30

16:45

8:33

18:21

9:38 19:44 22:06 11:17 20:35 10:20

15

6:23

16:40

8:34

18:22

9:37 19:43 22:03 11:13 20:31 10:16

16

6:17

16:34

8:35

18:24

9:35 19:42 21:59 11:09 20:27 10:12

17

6:10

16:29

8:36

18:26

9:33 19:41 21:55 11:06 20:22 10:08

18

6:05

16:24

8:37

18:28

9:31 19:40 21:51 11:02 20:18 10:04

19

5:59

16:19

8:37

18:30

9:29 19:39 21:47 10:58 20:14 10:00

20

5:54

16:15

8:38

18:31

9:27 19:38 21:43 10:54 20:10

9:56

21

5:49

16:10

8:39

18:33

9:25 19:38 21:39 10:50 20:06

9:52

22

5:44

16:06

8:40

18:35

9:24 19:37 21:35 10:46 20:02

9:48

23

5:40

16:02

8:40

18:37

9:22 19:36 21:31 10:42 19:58

9:44

24

5:37

15:58

8:41

18:39

9:20 19:35 21:27 10:38 19:53

9:40

25

5:33

15:55

8:41

18:41

9:18 19:34 21:23 10:34 19:49

9:36

26

5:30

15:51

8:42

18:43

9:16 19:33 21:19 10:30 19:45

9:32

27

5:28

15:48

8:42

18:45

9:14 19:32 21:15 10:26 19:41

9:27

28

5:26

15:46

8:43

18:47

9:12 19:31 21:11 10:22 19:37

9:23

29

5:24

15:43

8:43

18:49

9:10 19:30 21:07 10:18 19:32

9:19

30

5:23

15:41

8:43

18:51

9:08 19:29 21:03 10:14 19:28

9:15

2021 AUSTRAL ASIAN SKY GUIDE

83

JUN

9 10

Sun and twilight TWILIGHT START

JUN

Date

Day

SUN

TWILIGHT END

Nautical

Civil

Rise

Set

Civil

Nautical

1

Tuesday

5:53

6:24

6:52

16:54

17:22

17:53

2

Wednesday

5:54

6:25

6:52

16:54

17:21

17:52

3

Thursday

5:54

6:25

6:53

16:54

17:21

17:52

4

Friday

5:55

6:26

6:53

16:54

17:21

17:52

5

Saturday

5:55

6:26

6:54

16:53

17:21

17:52

6

Sunday

5:56

6:27

6:54

16:53

17:21

17:52

7

Monday

5:56

6:27

6:55

16:53

17:21

17:52

8

Tuesday

5:57

6:28

6:55

16:53

17:21

17:52

9

Wednesday

5:57

6:28

6:56

16:53

17:21

17:52

10

Thursday

5:58

6:29

6:56

16:53

17:20

17:52

11

Friday

5:58

6:29

6:57

16:53

17:20

17:52

12

Saturday

5:58

6:29

6:57

16:53

17:20

17:52

13

Sunday

5:59

6:30

6:58

16:53

17:21

17:52

14

Monday

5:59

6:30

6:58

16:53

17:21

17:52

15

Tuesday

5:59

6:31

6:58

16:53

17:21

17:52

16

Wednesday

6:00

6:31

6:59

16:53

17:21

17:52

17

Thursday

6:00

6:31

6:59

16:53

17:21

17:52

18

Friday

6:00

6:32

6:59

16:53

17:21

17:52

19

Saturday

6:01

6:32

7:00

16:53

17:21

17:52

20

Sunday

6:01

6:32

7:00

16:54

17:21

17:53

21

Monday

6:01

6:32

7:00

16:54

17:22

17:53

22

Tuesday

6:01

6:32

7:00

16:54

17:22

17:53

23

Wednesday

6:01

6:33

7:00

16:54

17:22

17:53

24

Thursday

6:02

6:33

7:01

16:55

17:22

17:54

25

Friday

6:02

6:33

7:01

16:55

17:23

17:54

26

Saturday

6:02

6:33

7:01

16:55

17:23

17:54

27

Sunday

6:02

6:33

7:01

16:56

17:23

17:55

28

Monday

6:02

6:33

7:01

16:56

17:24

17:55

29

Tuesday

6:02

6:33

7:01

16:56

17:24

17:55

30

Wednesday

6:02

6:33

7:01

16:57

17:24

17:56

84

2021 AUSTRAL ASIAN SKY GUIDE

Moon and tides MOON

TIMES AND HEIGHTS OF HIGH AND LOW WATERS Time

H (m)

Time

H (m)

Time

H (m)

Time

H (m)

Date

22:56 12:05

0:37

1.78

7:40

0.49

13:45

1.33

19:11

0.79

1

23:57 12:39

1:38

1.66

8:35

0.54

14:47

1.35

20:19

0.82

2

13:09

2:39

1.56

9:25

0.57

15:44

1.40

21:29

0.81

3

0:55 13:36

3:39

1.49

10:09

0.59

16:33

1.47

22:34

0.78

4

1:51 14:02

4:33

1.45

10:49

0.59

17:18

1.54

23:31

0.73

5

2:46 14:28

5:22

1.42

11:27

0.59

17:58

1.61

3:42 14:56

0:21

0.67

6:07

1.40

12:02

0.59

18:35

1.68

7

4:37 15:26

1:04

0.61

6:49

1.39

12:37

0.59

19:10

1.74

8

5:34 15:59

1:44

0.56

7:30

1.38

13:11

0.60

19:45

1.79

9

6:31 16:38

2:21

0.52

8:12

1.36

13:45

0.62

20:19

1.82

10

7:28 17:22

2:59

0.50

8:52

1.35

14:22

0.64

20:56

1.83

11

8:22 18:12

3:38

0.49

9:32

1.33

15:00

0.66

21:33

1.83

12

9:13 19:07

4:17

0.50

10:15

1.32

15:40

0.68

22:13

1.81

13

9:59 20:06

5:00

0.51

10:59

1.30

16:22

0.71

22:54

1.78

14

10:40 21:07

5:45

0.53

11:46

1.29

17:10

0.73

23:39

1.73

15

11:16 22:10

6:33

0.53

12:38

1.30

18:04

0.76

11:49 23:13

0:30

1.68

7:24

0.52

13:35

1.34

19:06

0.77

17

12:21

1:26

1.63

8:15

0.50

14:33

1.41

20:15

0.75

18

Rise

Set

6

12:51

0:17

2:28

1.59

9:05

0.48

15:30

1.52

21:28

0.70

19

13:23

1:22

3:33

1.56

9:56

0.46

16:26

1.64

22:40

0.61

20

13:57

2:30

4:38

1.54

10:46

0.44

17:19

1.78

23:46

0.50

21

14:36

3:41

5:40

1.52

11:36

0.44

18:12

1.90

15:21

4:54

0:47

0.39

6:41

1.50

12:28

0.44

19:03

2.01

23

16:15

6:08

1:45

0.30

7:40

1.48

13:19

0.45

19:56

2.07

24

17:16

7:19

2:41

0.24

8:37

1.46

14:11

0.48

20:47

2.09

25

18:23

8:22

3:34

0.23

9:32

1.44

15:03

0.51

21:39

2.07

26

19:32

9:15

4:28

0.27

10:27

1.41

15:57

0.56

22:29

1.99

27

20:40 10:00

5:19

0.32

11:20

1.39

16:49

0.61

23:18

1.87

28

21:44 10:37

6:10

0.40

12:13

1.37

17:44

0.67

22:45 11:09

0:07

1.74

6:58

0.47

13:05

1.36

22

29 18:39

0.73

30

Tidal predictions for Sydney only.

© Commonwealth of Australia, Bureau of Meteorology, National Tidal Centre.

2021 AUSTRAL ASIAN SKY GUIDE

85

JUN

16

JUL

KEY







Bright Star

Faint Star Magellanic Cloud



V1 VENUS ON 7 JULY V2 VENUS ON 21 JULY MARS M

86

2021 AUSTRAL ASIAN SKY GUIDE

This sky map shows the ZODIAC CONSTELLATIONS, Non-Zodiac Constellations and Stars of the night sky as seen from Sydney at: 6:30 pm on 7 July 5:30 pm on 21 July For other dates subtract or add half an hour each week.

JULY 2021 The evening sky See sky map opposite Scorpius, the Scorpion, with its curved line of bright stars is high in the eastern sky. Below it is the constellation of Sagittarius, the Archer. In old drawings of the constellation, the Archer is depicted as a centaur — a half-human and half-horse creature like the constellation Centaurus. The common name of Sagittarius, however, is the Teapot. The aptness of this name can be verified by a quick glance at the stars of the constellation, with the handle below, the spout above and the lid to the left or north. Spica, the brightest star in the constellation of Virgo, is high in the north. This star, at a distance of 250 light years from us, consists of two hot and massive stars whirling around each other every four days. They are so close that they cannot be seen as separate stars through a telescope. Instead, astronomers use a device called a spectrograph, which breaks the starlight into its component colours and allows them to measure the velocities of the two stars as they alternately approach and move away from us. Below Spica we find the brilliant orange-coloured Arcturus, the brightest star in the constellation of Boötes, the Herdsman. July is the best time to view this star, which is one of the brightest as viewed from the northern hemisphere. The Southern Cross is high in the south with the pointer stars, Rigil Kentaurus and Beta Centauri, almost vertical. These two stars are part of the large constellation of Centaurus, the Centaur. D I A R Y F O R J U LY 2 0 2 1

2

Friday

Last quarter

7:11 am

6

Tuesday

Earth furthest from the Sun (aphelion)

8:27 am

10

Saturday

New Moon

11:17 am

17

Saturday

First quarter

8:11 pm

24

Saturday

Full Moon

12:37 pm

31

Saturday

Last quarter

11:16 pm

2021 AUSTRAL ASIAN SKY GUIDE

87

Evening twilight Venus and Mars have a conjunction as they are joined by Saturn. Venus is in the north-west, starting the month in Cancer and following Mars into Leo in the second week. On 12 July a thin crescent Moon is below and north of Venus. On 13 July Venus passes Mars at a separation of one moon-width. On 22 July Venus passes the bright star Regulus at a separation of just over two moon-widths. Mars is in the north-west, moving from Cancer to Leo in the second week. On 30 July it passes Regulus at a separation of one moon-width. Saturn appears low in the east just after the middle of the month in Capricornus. On 24 July the full Moon is above and south of Saturn.

Morning twilight Mercury is low in the north-east. It starts the month in Taurus, races through part of Orion in two days and finishes up in Gemini. On 8 July a very thin crescent Moon is to the left or north of Mercury. The planet disappears into the twilight just after the middle of the month. Jupiter is in the west in Aquarius. On 26 July the gibbous Moon is left or south of Jupiter, while the next morning it is above and north. Saturn is in the west in Capricornus. On 25 July the gibbous Moon is above and to the south of Saturn. 6:00 pm on 12 July — two planets and the crescent Moon

88

2021 AUSTRAL ASIAN SKY GUIDE

Planets MERCURY Date

VENUS

MARS Set

JUPITER Rise

Set

SATURN

Rise

Set

Rise

Set

Rise

1

5:22

15:39

8:43

18:53

9:06

19:29 20:59 10:10 19:24

Rise

9:11

Set

2

5:21

15:37

8:44

18:55

9:04

19:28 20:55 10:06 19:20

9:07

3

5:21

15:36

8:44

18:57

9:02

19:27 20:51 10:02 19:16

9:03

4

5:21

15:34

8:44

18:59

9:00

19:26 20:47

9:58 19:11

8:59

5

5:22

15:34

8:44

19:01

8:58

19:25 20:42

9:54 19:07

8:55

6

5:22

15:33

8:44

19:03

8:56

19:24 20:38

9:50 19:03

8:51

7

5:24

15:33

8:44

19:05

8:54

19:23 20:34

9:46 18:59

8:46

8

5:25

15:33

8:44

19:07

8:52

19:22 20:30

9:42 18:54

8:42

5:27

15:33

8:44

19:09

8:50

19:21 20:26

9:38 18:50

8:38

5:29

15:34

8:43

19:11

8:48

19:20 20:21

9:34 18:46

8:34

11

5:32

15:35

8:43

19:13

8:46

19:20 20:17

9:30 18:42

8:30

12

5:35

15:37

8:43

19:15

8:44

19:19 20:13

9:26 18:37

8:26

13

5:38

15:38

8:43

19:17

8:42

19:18 20:09

9:22 18:33

8:22

14

5:41

15:41

8:42

19:18

8:40

19:17 20:04

9:18 18:29

8:18

15

5:44

15:43

8:42

19:20

8:38

19:16 20:00

9:13 18:25

8:13

16

5:48

15:46

8:42

19:22

8:36

19:15 19:56

9:09 18:20

8:09

17

5:52

15:49

8:41

19:24

8:33

19:14 19:51

9:05 18:16

8:05

18

5:56

15:53

8:41

19:26

8:31

19:13 19:47

9:01 18:12

8:01

19

6:00

15:57

8:40

19:28

8:29

19:12 19:43

8:57 18:08

7:57

20

6:04

16:01

8:40

19:30

8:27

19:11 19:38

8:53 18:03

7:53

21

6:09

16:06

8:39

19:32

8:25

19:11 19:34

8:49 17:59

7:49

22

6:13

16:10

8:38

19:34

8:23

19:10 19:30

8:44 17:55

7:44

23

6:18

16:16

8:38

19:36

8:21

19:09 19:25

8:40 17:50

7:40

24

6:22

16:21

8:37

19:38

8:19

19:08 19:21

8:36 17:46

7:36

25

6:26

16:27

8:37

19:40

8:16

19:07 19:16

8:32 17:42

7:32

26

6:31

16:33

8:36

19:41

8:14

19:06 19:12

8:28 17:38

7:28

27

6:35

16:39

8:35

19:43

8:12

19:05 19:08

8:23 17:33

7:24

28

6:39

16:45

8:34

19:45

8:10

19:04 19:03

8:19 17:29

7:19

29

6:43

16:51

8:34

19:47

8:08

19:03 18:59

8:15 17:25

7:15

30

6:46

16:57

8:33

19:49

8:06

19:02 18:54

8:11 17:20

7:11

31

6:50

17:03

8:32

19:51

8:03

19:02 18:50

8:07 17:16

7:07

2021 AUSTRAL ASIAN SKY GUIDE

89

JUL

9 10

Sun and twilight TWILIGHT START

JUL

Date

Day

SUN

TWILIGHT END

Nautical

Civil

Rise

Set

Civil

Nautical

1

Thursday

6:02

6:33

7:01

16:57

17:25

17:56

2

Friday

6:02

6:33

7:01

16:58

17:25

17:56

3

Saturday

6:02

6:33

7:01

16:58

17:26

17:57

4

Sunday

6:02

6:33

7:01

16:58

17:26

17:57

5

Monday

6:02

6:33

7:01

16:59

17:26

17:58

6

Tuesday

6:02

6:33

7:01

16:59

17:27

17:58

7

Wednesday

6:02

6:33

7:00

17:00

17:27

17:58

8

Thursday

6:02

6:33

7:00

17:00

17:28

17:59

9

Friday

6:02

6:33

7:00

17:01

17:28

17:59

10

Saturday

6:01

6:32

7:00

17:01

17:29

18:00

11

Sunday

6:01

6:32

7:00

17:02

17:29

18:00

12

Monday

6:01

6:32

6:59

17:03

17:30

18:01

13

Tuesday

6:01

6:32

6:59

17:03

17:31

18:01

14

Wednesday

6:00

6:31

6:59

17:04

17:31

18:02

15

Thursday

6:00

6:31

6:58

17:04

17:32

18:02

16

Friday

6:00

6:31

6:58

17:05

17:32

18:03

17

Saturday

6:00

6:30

6:57

17:06

17:33

18:03

18

Sunday

5:59

6:30

6:57

17:06

17:33

18:04

19

Monday

5:59

6:29

6:56

17:07

17:34

18:05

20

Tuesday

5:58

6:29

6:56

17:08

17:35

18:05

21

Wednesday

5:58

6:28

6:55

17:08

17:35

18:06

22

Thursday

5:57

6:28

6:55

17:09

17:36

18:06

23

Friday

5:57

6:27

6:54

17:09

17:36

18:07

24

Saturday

5:56

6:27

6:54

17:10

17:37

18:07

25

Sunday

5:56

6:26

6:53

17:11

17:38

18:08

26

Monday

5:55

6:26

6:52

17:11

17:38

18:09

27

Tuesday

5:55

6:25

6:52

17:12

17:39

18:09

28

Wednesday

5:54

6:24

6:51

17:13

17:39

18:10

29

Thursday

5:53

6:24

6:50

17:14

17:40

18:10

30

Friday

5:53

6:23

6:49

17:14

17:41

18:11

31

Saturday

5:52

6:22

6:49

17:15

17:41

18:11

90

2021 AUSTRAL ASIAN SKY GUIDE

Moon and tides MOON

TIMES AND HEIGHTS OF HIGH AND LOW WATERS Time

H (m)

Time

H (m)

Time

H (m)

Time

H (m)

Date

23:43 11:38

0:57

1.60

7:44

0.54

13:58

1.38

19:40

0.78

1

Rise

Set

12:05

1:48

1.47

8:28

0.58

14:51

1.41

20:45

0.81

2

0:39 12:31

2:45

1.37

9:11

0.61

15:43

1.46

21:55

0.79

3

1:34 12:58

3:44

1.31

9:54

0.62

16:32

1.52

23:00

0.74

4

2:30 13:27

4:42

1.28

10:38

0.62

17:17

1.59

23:57

0.68

5

3:27 13:59

5:36

1.27

11:21

0.62

18:00

1.65

4:24 14:36

0:43

0.60

6:26

1.28

12:02

0.62

18:40

1.71

7

5:21 15:18

1:24

0.54

7:11

1.29

12:42

0.61

19:19

1.77

8

6:16 16:06

2:02

0.48

7:52

1.31

13:22

0.60

19:57

1.81

9

7:09 17:01

2:41

0.44

8:32

1.32

14:01

0.59

20:35

1.84

10

7:57 17:59

3:18

0.42

9:12

1.33

14:42

0.58

21:15

1.85

11

8:40 19:01

3:57

0.41

9:53

1.34

15:23

0.58

21:54

1.84

12

9:18 20:03

4:37

0.40

10:36

1.35

16:08

0.59

22:35

1.81

13

9:52 21:06

5:18

0.41

11:22

1.36

16:56

0.61

23:19

1.76

14

10:23 22:10

6:01

0.42

12:11

1.39

17:49

0.64

10:54 23:13

0:06

1.68

6:46

0.43

13:03

1.43

18:48

0.66

16

11:24

6

15

1.58

7:33

0.45

13:59

1.49

19:57

0.67

17

0:19

2:00

1.48

8:25

0.47

14:58

1.57

21:14

0.64

18

12:32

1:26

3:10

1.41

9:19

0.49

15:58

1.66

22:30

0.56

19

13:13

2:36

4:22

1.36

10:16

0.50

16:58

1.77

23:42

0.46

20

14:01

3:48

5:31

1.35

11:15

0.49

17:55

1.87

14:58

4:58

0:44

0.35

6:35

1.37

12:12

0.48

18:50

1.96

22

16:02

6:04

1:39

0.27

7:32

1.39

13:06

0.46

19:44

2.01

23

17:10

7:02

2:30

0.22

8:26

1.41

13:59

0.45

20:33

2.02

24

18:19

7:51

3:18

0.22

9:15

1.42

14:49

0.45

21:21

1.98

25

19:26

8:31

4:03

0.25

10:02

1.42

15:39

0.48

22:07

1.90

26

20:30

9:06

4:46

0.31

10:48

1.41

16:27

0.53

22:50

1.78

27

21:30

23:31

1.64

28

21

9:37

5:28

0.38

11:33

1.40

17:15

0.59

22:28 10:05

6:06

0.45

12:18

1.40

18:04

0.66

23:25 10:32

0:13

1.50

6:45

0.52

13:04

1.40

18:59

0.72

30

10:59

0:58

1.37

7:23

0.58

13:53

1.41

20:01

0.76

31

29

Tidal predictions for Sydney only.

© Commonwealth of Australia, Bureau of Meteorology, National Tidal Centre.

2021 AUSTRAL ASIAN SKY GUIDE

91

JUL

1:00

11:56

AUG

KEY







Bright Star

Faint Star



Magellanic Cloud

M2 MERCURY ON 21 AUGUST V1 VENUS ON 7 AUGUST

V2 VENUS ON 21 AUGUST JUPITER J SATURN S

92

2021 AUSTRAL ASIAN SKY GUIDE

This sky map shows the ZODIAC CONSTELLATIONS, Non-Zodiac Constellations and Stars of the night sky as seen from Sydney at: 7:30 pm on 7 August 6:30 pm on 21 August For other dates subtract or add half an hour each week.

AUGUST 2021 The evening sky See sky map opposite The constellation of Sagittarius, the Archer, is high in the eastern sky. More commonly known as the Teapot, the handle is below and the spout above. The lower star on the left or north of the handle has the name Nunki, of Babylonian origin. At a distance of 225 light years from us, the star is fast-spinning and exceptionally hot. Above Sagittarius we find the curved line of bright stars forming Scorpius, the Scorpion, almost directly overhead. Its claws lie towards the west, while the tail is towards the east. Antares, the Scorpion’s red heart, shines brightly near the zenith. Its name means ‘Rival of Mars’, as the planet Mars is a similar colour and brightness. In the north-east we see Altair, the brightest star in the constellation of Aquila, the Eagle. Altair can be easily recognised as it is flanked by two stars, Tarazed to the left or north and Alshain to the right or east. Closer to the horizon than Altair and to its left or north, we see Vega, the brightest star in the constellation of Lyra, the Lyre. Thirteen thousand years ago Vega marked the pole in the northern hemisphere sky just as Polaris does today. In the southern part of the sky the Southern Cross is high in the south-west. Though we normally think of the Cross as consisting of five bright stars, the fifth star Ginan is becoming difficult to see from our over-lit cities and suburbs. Ginan appears faint to us because of its great distance of 228 light years from Earth. Despite this, the star is part of the representation of the Southern Cross on the Australian flag but is strangely missing from that of New Zealand.

DIARY FOR AUGUST 2021

8

Sunday

New Moon

11:50 pm

16

Monday

First quarter

1:20 am

22

Sunday

Full Moon

30

Monday

Last quarter

10:02 pm 5:13 pm

2021 AUSTRAL ASIAN SKY GUIDE

93

Evening twilight Mercury and Jupiter join the three previous evening planets. Mercury is low in the west in the middle of the month, moving from Leo into Virgo near the end. On 19 August Mercury passes Mars at a separation of only half a moon-width. Venus is in the west, moving from Leo into Virgo in the second week. On 11 August the crescent Moon is below and north of Venus. Mars is low in the west in Leo but disappears at month’s end. On 10 August a very thin crescent Moon is to the right or north of Mars. Jupiter is low in the east in Aquarius in the second week but moves into Capricornus in the third week. On 20 August Jupiter is at opposition and at its brightest for the year. On 22 August the full Moon is below and to the south of Jupiter. Saturn is in the east in Capricornus. On 2 August it is at opposition and its brightest for the year. On 20 August the gibbous Moon is above and south of Saturn, on 21 August it is below it but south.

Morning twilight Jupiter is low in the west. Saturn is very low in the west and disappears below the horizon in the last week. 6:15 pm on 18 August — three planets

94

2021 AUSTRAL ASIAN SKY GUIDE

Planets MERCURY Date

VENUS

MARS Set

JUPITER Rise

SATURN

Rise

Set

Rise

Set

Rise

Set

Rise

Set

1

6:53

17:10

8:31

19:52

8:01

19:01 18:45

8:02

17:12

7:03

2

6:56

17:16

8:30

19:54

7:59

19:00 18:41

7:58

17:07

6:59

3

6:59

17:22

8:29

19:56

7:57

18:59 18:36

7:54

17:03

6:54

4

7:02

17:28

8:28

19:58

7:55

18:58 18:32

7:50

16:59

6:50

5

7:04

17:34

8:28

20:00

7:52

18:57 18:27

7:45

16:55

6:46

6

7:06

17:40

8:27

20:01

7:50

18:56 18:23

7:41

16:50

6:42

7

7:09

17:46

8:26

20:03

7:48

18:55 18:18

7:37

16:46

6:38

8

7:10

17:52

8:25

20:05

7:46

18:54 18:14

7:33

16:42

6:34

7:12

17:57

8:24

20:07

7:44

18:53 18:09

7:28

16:37

6:29

7:14

18:03

8:23

20:08

7:41

18:52 18:05

7:24

16:33

6:25

11

7:15

18:08

8:22

20:10

7:39

18:52 18:00

7:20

16:29

6:21

12

7:16

18:13

8:21

20:12

7:37

18:51 17:55

7:15

16:25

6:17

13

7:17

18:18

8:20

20:13

7:35

18:50 17:51

7:11

16:20

6:13

14

7:18

18:23

8:19

20:15

7:32

18:49 17:46

7:07

16:16

6:09

15

7:19

18:28

8:18

20:17

7:30

18:48 17:42

7:03

16:12

6:05

16

7:19

18:32

8:16

20:19

7:28

18:47 17:37

6:58

16:07

6:00

17

7:20

18:37

8:15

20:20

7:26

18:46 17:33

6:54

16:03

5:56

18

7:20

18:41

8:14

20:22

7:23

18:45 17:28

6:50

15:59

5:52

19

7:20

18:46

8:13

20:24

7:21

18:44 17:23

6:45

15:55

5:48

20

7:20

18:50

8:12

20:25

7:19

18:43 17:19

6:41

15:50

5:44

21

7:20

18:54

8:11

20:27

7:16

18:43 17:14

6:37

15:46

5:40

22

7:20

18:58

8:10

20:29

7:14

18:42 17:10

6:32

15:42

5:35

23

7:20

19:01

8:09

20:30

7:12

18:41 17:05

6:28

15:38

5:31

24

7:20

19:05

8:08

20:32

7:10

18:40 17:01

6:24

15:33

5:27

25

7:19

19:08

8:07

20:34

7:07

18:39 16:56

6:20

15:29

5:23

26

7:19

19:12

8:06

20:35

7:05

18:38 16:52

6:15

15:25

5:19

27

7:18

19:15

8:05

20:37

7:03

18:37 16:47

6:11

15:21

5:15

28

7:18

19:18

8:03

20:39

7:01

18:36 16:42

6:07

15:16

5:11

29

7:17

19:21

8:02

20:41

6:58

18:35 16:38

6:02

15:12

5:06

30

7:16

19:24

8:01

20:42

6:56

18:34 16:33

5:58

15:08

5:02

31

7:15

19:27

8:00

20:44

6:54

18:33 16:29

5:54

15:04

4:58

2021 AUSTRAL ASIAN SKY GUIDE

95

AUG

9 10

Sun and twilight TWILIGHT START

AUG

Date

Day

SUN

TWILIGHT END

Nautical

Civil

Rise

Set

Civil

Nautical

1

Sunday

5:51

6:21

6:48

17:16

17:42

18:12

2

Monday

5:51

6:21

6:47

17:16

17:43

18:13

3

Tuesday

5:50

6:20

6:46

17:17

17:43

18:13

4

Wednesday

5:49

6:19

6:45

17:18

17:44

18:14

5

Thursday

5:48

6:18

6:44

17:18

17:45

18:14

6

Friday

5:47

6:17

6:43

17:19

17:45

18:15

7

Saturday

5:47

6:16

6:43

17:20

17:46

18:16

8

Sunday

5:46

6:15

6:42

17:21

17:47

18:16

9

Monday

5:45

6:15

6:41

17:21

17:47

18:17

10

Tuesday

5:44

6:14

6:40

17:22

17:48

18:18

11

Wednesday

5:43

6:13

6:39

17:23

17:49

18:18

12

Thursday

5:42

6:12

6:38

17:23

17:49

18:19

13

Friday

5:41

6:11

6:37

17:24

17:50

18:19

14

Saturday

5:40

6:10

6:35

17:25

17:51

18:20

15

Sunday

5:39

6:09

6:34

17:25

17:51

18:21

16

Monday

5:38

6:08

6:33

17:26

17:52

18:21

17

Tuesday

5:37

6:07

6:32

17:27

17:53

18:22

18

Wednesday

5:36

6:05

6:31

17:28

17:53

18:23

19

Thursday

5:35

6:04

6:30

17:28

17:54

18:23

20

Friday

5:34

6:03

6:29

17:29

17:54

18:24

21

Saturday

5:33

6:02

6:28

17:30

17:55

18:24

22

Sunday

5:32

6:01

6:26

17:30

17:56

18:25

23

Monday

5:31

6:00

6:25

17:31

17:56

18:26

24

Tuesday

5:29

5:59

6:24

17:32

17:57

18:26

25

Wednesday

5:28

5:57

6:23

17:32

17:58

18:27

26

Thursday

5:27

5:56

6:21

17:33

17:58

18:27

27

Friday

5:26

5:55

6:20

17:34

17:59

18:28

28

Saturday

5:25

5:54

6:19

17:34

18:00

18:29

29

Sunday

5:24

5:53

6:18

17:35

18:00

18:29

30

Monday

5:22

5:51

6:16

17:36

18:01

18:30

31

Tuesday

5:21

5:50

6:15

17:36

18:02

18:31

96

2021 AUSTRAL ASIAN SKY GUIDE

Moon and tides MOON

TIMES AND HEIGHTS OF HIGH AND LOW WATERS Time

H (m)

Time

H (m)

Time

H (m)

Time

H (m)

Date

0:21 11:27

1:50

1.26

8:07

0.62

14:46

1.43

21:14

0.76

1

1:18 11:58

2:55

1.18

8:58

0.65

15:42

1.47

22:27

0.72

2

2:15 12:33

4:06

1.16

9:53

0.66

16:37

1.52

23:30

0.65

3

3:12 13:13

5:13

1.17

10:46

0.66

17:28

1.58

4:08 13:59

0:20

0.57

6:07

1.20

11:36

0.63

18:14

1.65

5

5:02 14:51

1:02

0.49

6:52

1.24

12:21

0.59

18:56

1.72

6

5:52 15:49

1:41

0.42

7:32

1.29

13:03

0.54

19:35

1.79

7

6:37 16:51

2:16

0.37

8:11

1.33

13:44

0.50

20:15

1.84

8

7:17 17:54

2:53

0.32

8:49

1.37

14:25

0.46

20:53

1.86

9

7:53 18:58

3:30

0.29

9:29

1.41

15:09

0.45

21:33

1.85

10

8:25 20:03

4:07

0.28

10:11

1.45

15:54

0.45

22:15

1.80

11

8:56 21:07

4:46

0.29

10:55

1.48

16:44

0.47

23:00

1.72

12

9:27 22:12

5:27

0.33

11:42

1.51

17:37

0.50

23:47

1.60

13

9:58 23:19

6:09

0.38

12:32

1.54

18:38

0.55

Rise

Set

10:32

4

14

0:41

1.46

6:57

0.45

13:28

1.56

19:48

0.57

15

11:11

0:27

1:45

1.34

7:50

0.51

14:30

1.59

21:10

0.56

16

11:55

1:37

3:01

1.25

8:53

0.56

15:38

1.64

22:30

0.50

17

12:47

2:46

4:22

1.22

10:01

0.57

16:45

1.72

23:41

0.41

18

13:47

3:52

5:34

1.25

11:06

0.54

17:46

1.80

14:53

4:51

0:39

0.32

6:33

1.31

12:06

0.49

18:42

1.87

20

16:00

5:42

1:29

0.25

7:24

1.37

13:00

0.43

19:31

1.91

21

17:08

6:26

2:13

0.22

8:10

1.42

13:49

0.40

20:17

1.90

22

18:13

7:03

2:54

0.22

8:52

1.45

14:35

0.39

21:00

1.85

23

19:15

7:35

3:31

0.25

9:33

1.47

15:19

0.41

21:41

1.76

24

20:15

8:04

4:07

0.31

10:13

1.47

16:02

0.46

22:18

1.65

25

21:13

8:31

4:41

0.38

10:51

1.47

16:45

0.52

22:55

1.52

26

22:10

8:58

5:12

0.45

11:30

1.46

17:30

0.58

23:32

1.39

27

23:07

9:26

5:44

0.52

12:10

1.45

18:20

0.64

9:56

0:15

1.28

6:19

0.59

12:54

1.43

19:19

0.69

29

0:04 10:30

1:06

1.17

7:03

0.65

13:46

1.42

20:30

0.70

30

1:02 11:07

2:13

1.10

8:00

0.70

14:48

1.42

21:48

0.68

31

19

Tidal predictions for Sydney only.

© Commonwealth of Australia, Bureau of Meteorology, National Tidal Centre.

2021 AUSTRAL ASIAN SKY GUIDE

97

AUG

28

SEP

KEY







Bright Star

Faint Star



Magellanic Cloud

M1 MERCURY ON 7 SEPTEMBER

M2 MERCURY ON 21 SEPTEMBER V1 VENUS ON 7 SEPTEMBER V2 VENUS ON 21 SEPTEMBER JUPITER J SATURN S

98

2021 AUSTRAL ASIAN SKY GUIDE

This sky map shows the ZODIAC CONSTELLATIONS, Non-Zodiac Constellations and Stars of the night sky as seen from Sydney at: 7:30 pm on 7 September 6:30 pm on 21 September For other dates subtract or add half an hour each week.

SEPTEMBER 2021 The evening sky See sky map opposite The constellation of Sagittarius, the Archer, is overhead while Scorpius, the Scorpion, with its bright red star Antares is high in the western sky. Altair, the brightest star in the constellation of Aquila, the Eagle, is prominent in the north together with its two attendant stars, one on either side. Below Altair and due north, we find Vega, the brightest star in the constellation of Lyra, the Lyre. September is the best time to see this star, which is prominent from the northern hemisphere as it is below our horizon for most of the year. A little south of east we can see Fomalhaut, the brightest star in the constellation of Pisces Austrinus, the Southern Fish. The star is 25 light years from us and is surrounded by a disc of dusty debris, within which astronomers have detected a planet circling the star. The Southern Cross is almost on its side in the south-west. If we extend an imaginary line through the main axis of the Cross towards the left or east, near the horizon we reach Achernar, the brightest star of the constellation of Eridanus, the River.

Equinox The spring equinox occurs when the Sun crosses from the northern to the southern part of the sky. This takes place on 23 September this year. As at the autumn equinox in March, the Sun rises close to due east and sets close to due west. As well, daytime and night-time are close to equal length. DIARY FOR SEPTEMBER 2021

7

Tuesday

New Moon

10:52 am

14

Tuesday

First quarter

6:39 am

21

Tuesday

Full Moon

9:55 am

23

Thursday

Spring equinox

5:21 am

26

Sunday

Summer time begins (NZ)

2:00 am

29

Wednesday

Last quarter

11:57 am

2021 AUSTRAL ASIAN SKY GUIDE

99

Evening twilight Mars is out of view but the four other naked eye planets continue to brighten the evening sky. Mercury is low in the west in Virgo. On 9 September a thin crescent Moon is above and to the right or north of Mercury. From 19 September to the end of the month Mercury is close to the bright star Spica. Venus is in the west, above Mercury. It starts the month in Virgo and moves into Libra just after the middle of the month. On 5–6 September Venus passes Spica at a separation of just under four moon-widths. On 10 September a thin crescent Moon is above and to the right or north of Venus. Jupiter is in the east in Capricornus. On 18 September the gibbous Moon is to the right or south of Jupiter. Saturn is in the east, above Jupiter, and also in Capricornus. On 17 September the gibbous Moon is below and to the right or south of Saturn.

Morning twilight Jupiter is very low in the west at the start of the month but disappears below the horizon in the middle of the second week of the month. 6:45 pm on 10 September — two planets and the crescent Moon

100 2021 AUSTRAL ASIAN SKY GUIDE

Planets MERCURY Date

VENUS

MARS Set

JUPITER Rise

SATURN

Rise

Set

Rise

Set

Rise

Set

Rise

Set

1

7:15

19:30

7:59

20:46

6:51

18:33 16:24

5:50

14:59

4:54

2

7:14

19:33

7:58

20:47

6:49

18:32 16:20

5:45

14:55

4:50

3

7:13

19:35

7:57

20:49

6:47

18:31 16:15

5:41

14:51

4:46

4

7:11

19:38

7:56

20:51

6:45

18:30 16:11

5:37

14:47

4:42

5

7:10

19:40

7:55

20:52

6:42

18:29 16:06

5:32

14:43

4:38

6

7:09

19:42

7:54

20:54

6:40

18:28 16:02

5:28

14:38

4:34

7

7:08

19:44

7:53

20:56

6:38

18:27 15:57

5:24

14:34

4:29

8

7:06

19:46

7:52

20:57

6:35

18:26 15:53

5:20

14:30

4:25

7:05

19:48

7:51

20:59

6:33

18:25 15:48

5:15

14:26

4:21

7:04

19:49

7:50

21:01

6:31

18:25 15:44

5:11

14:22

4:17

11

7:02

19:51

7:49

21:03

6:29

18:24 15:39

5:07

14:18

4:13

12

7:00

19:52

7:48

21:04

6:26

18:23 15:35

5:03

14:13

4:09

13

6:59

19:53

7:47

21:06

6:24

18:22 15:30

4:58

14:09

4:05

14

6:57

19:54

7:46

21:08

6:22

18:21 15:26

4:54

14:05

4:01

15

6:55

19:55

7:45

21:09

6:19

18:20 15:22

4:50

14:01

3:57

16

6:53

19:55

7:44

21:11

6:17

18:19 15:17

4:46

13:57

3:53

17

6:51

19:55

7:43

21:13

6:15

18:18 15:13

4:41

13:53

3:49

18

6:48

19:55

7:43

21:15

6:13

18:18 15:08

4:37

13:49

3:45

19

6:46

19:55

7:42

21:16

6:10

18:17 15:04

4:33

13:45

3:41

20

6:43

19:54

7:41

21:18

6:08

18:16 15:00

4:29

13:40

3:37

21

6:41

19:53

7:40

21:20

6:06

18:15 14:55

4:25

13:36

3:32

22

6:38

19:52

7:39

21:22

6:03

18:14 14:51

4:20

13:32

3:28

23

6:35

19:50

7:39

21:23

6:01

18:13 14:47

4:16

13:28

3:24

24

6:32

19:48

7:38

21:25

5:59

18:12 14:42

4:12

13:24

3:20

25

6:28

19:45

7:37

21:27

5:57

18:12 14:38

4:08

13:20

3:16

26

6:25

19:42

7:36

21:29

5:54

18:11 14:34

4:04

13:16

3:12

27

6:21

19:38

7:36

21:30

5:52

18:10 14:29

4:00

13:12

3:08

28

6:17

19:34

7:35

21:32

5:50

18:09 14:25

3:56

13:08

3:04

29

6:13

19:29

7:35

21:34

5:48

18:08 14:21

3:51

13:04

3:00

30

6:08

19:23

7:34

21:35

5:45

18:07 14:17

3:47

13:00

2:56

2021 AUSTRAL ASIAN SKY GUIDE

101

SEP

9 10

Sun and twilight TWILIGHT START

SEP

Date

SUN

TWILIGHT END

Day

Nautical

Civil

Rise

Set

Civil

Nautical

1

Wednesday

5:20

5:49

6:14

17:37

18:02

18:31

2

Thursday

5:18

5:47

6:13

17:38

18:03

18:32

3

Friday

5:17

5:46

6:11

17:38

18:04

18:33

4

Saturday

5:16

5:45

6:10

17:39

18:04

18:33

5

Sunday

5:15

5:44

6:09

17:40

18:05

18:34

6

Monday

5:13

5:42

6:07

17:41

18:06

18:34

7

Tuesday

5:12

5:41

6:06

17:41

18:06

18:35

8

Wednesday

5:11

5:40

6:04

17:42

18:07

18:36

9

Thursday

5:09

5:38

6:03

17:43

18:08

18:36

10

Friday

5:08

5:37

6:02

17:43

18:08

18:37

11

Saturday

5:07

5:35

6:00

17:44

18:09

18:38

12

Sunday

5:05

5:34

5:59

17:45

18:09

18:38

13

Monday

5:04

5:33

5:58

17:45

18:10

18:39

14

Tuesday

5:02

5:31

5:56

17:46

18:11

18:40

15

Wednesday

5:01

5:30

5:55

17:47

18:12

18:40

16

Thursday

5:00

5:29

5:53

17:47

18:12

18:41

17

Friday

4:58

5:27

5:52

17:48

18:13

18:42

18

Saturday

4:57

5:26

5:51

17:49

18:14

18:43

19

Sunday

4:55

5:24

5:49

17:49

18:14

18:43

20

Monday

4:54

5:23

5:48

17:50

18:15

18:44

21

Tuesday

4:53

5:22

5:46

17:51

18:16

18:45

22

Wednesday

4:51

5:20

5:45

17:51

18:16

18:45

23

Thursday

4:50

5:19

5:44

17:52

18:17

18:46

24

Friday

4:48

5:17

5:42

17:53

18:18

18:47

25

Saturday

4:47

5:16

5:41

17:53

18:18

18:48

26

Sunday

4:45

5:15

5:40

17:54

18:19

18:48

27

Monday

4:44

5:13

5:38

17:55

18:20

18:49

28

Tuesday

4:43

5:12

5:37

17:56

18:21

18:50

29

Wednesday

4:41

5:10

5:35

17:56

18:21

18:51

30

Thursday

4:40

5:09

5:34

17:57

18:22

18:51

102

2021 AUSTRAL ASIAN SKY GUIDE

Moon and tides MOON

TIMES AND HEIGHTS OF HIGH AND LOW WATERS Time

H (m)

Time

H (m)

Time

H (m)

Time

H (m)

Date

1:58 11:51

3:35

1.08

9:10

0.72

15:54

1.45

22:57

0.62

1

2:53 12:40

4:50

1.11

10:15

0.69

16:54

1.51

23:50

0.54

2

3:44 13:36

5:45

1.17

11:13

0.64

17:45

1.59

4:31 14:36

0:32

0.45

6:29

1.24

12:00

0.57

18:29

1.68

4

5:13 15:39

1:10

0.37

7:07

1.32

12:44

0.49

19:09

1.76

5

5:51 16:44

1:45

0.30

7:44

1.40

13:26

0.41

19:49

1.82

6

6:25 17:50

2:21

0.24

8:22

1.47

14:09

0.36

20:30

1.84

7

6:57 18:56

2:57

0.21

9:01

1.55

14:54

0.32

21:12

1.81

8

7:28 20:02

3:33

0.21

9:44

1.61

15:43

0.31

21:56

1.74

9

7:59 21:10

4:13

0.25

10:28

1.65

16:34

0.34

22:43

1.63

10

8:33 22:19

4:53

0.32

11:15

1.66

17:30

0.38

23:34

1.48

11

9:10 23:29

5:37

0.41

12:05

1.65

18:33

0.44

9:53

Rise

Set

3

12

0:32

1.34

6:26

0.51

13:02

1.63

19:47

0.49

13

10:42

0:39

1:43

1.22

7:27

0.59

14:10

1.61

21:11

0.49

14

11:39

1:45

3:07

1.16

8:40

0.64

15:25

1.62

22:29

0.45

15

12:42

2:46

4:30

1.19

9:57

0.62

16:37

1.66

23:32

0.38

16

13:48

3:39

5:33

1.26

11:05

0.56

17:38

1.72

14:55

4:23

0:24

0.32

6:24

1.34

12:02

0.49

18:30

1.76

18

15:59

5:01

1:08

0.28

7:07

1.42

12:53

0.42

19:15

1.77

19

17:02

5:34

1:46

0.26

7:47

1.48

13:38

0.38

19:57

1.75

20

18:02

6:04

2:21

0.27

8:25

1.53

14:20

0.37

20:35

1.69

21

19:01

6:32

2:53

0.30

9:01

1.56

15:00

0.38

21:12

1.61

22

19:59

6:59

3:23

0.35

9:36

1.57

15:41

0.42

21:47

1.51

23

20:56

7:26

3:52

0.41

10:10

1.57

16:20

0.46

22:23

1.41

24

21:54

7:55

4:21

0.48

10:45

1.56

17:02

0.51

23:01

1.31

25

22:51

8:27

4:51

0.55

11:21

1.53

17:48

0.56

23:44

1.22

26

23:48

9:03

5:27

0.62

12:02

1.49

18:43

0.61

17

9:44

0:34

1.14

6:11

0.69

12:53

1.45

19:48

0.65

28

0:44 10:30

1:40

1.08

7:11

0.75

13:54

1.41

21:04

0.64

29

1:36 11:23

3:01

1.08

8:26

0.77

15:06

1.42

22:14

0.60

30

Tidal predictions for Sydney only.

© Commonwealth of Australia, Bureau of Meteorology, National Tidal Centre.

2021 AUSTRAL ASIAN SKY GUIDE

103

SEP

27

KEY









Bright Star

Faint Star Magellanic Cloud

OCT

V1 VENUS ON 7 OCTOBER V22 VENUS ON 21 OCTOBER M J JUPITER SATURN S

104 2021 AUSTRAL ASIAN SKY GUIDE

This sky map shows the ZODIAC CONSTELLATIONS, Non-Zodiac Constellations and Stars of the night sky as seen from Sydney at: 8:30 pm on 7 October 7:30 pm on 21 October For other dates subtract or add half an hour each week.

OCTOBER 2021 The evening sky See sky map opposite Scorpius, the Scorpion, is upside down low in the western sky. Its claws are near the horizon while its tail is up in the sky. At the end of the long tail we find the star Shaula, its name coming from an Arabic phrase meaning ‘the sting’. At a distance of 365 light years from us, Shaula is an interesting triple-star system with two hot massive stars and a third star that could be a white dwarf star (a compact and dense object) or a star that is still forming. Altair, the brightest star in the constellation of Aquila, the Eagle, is high in the northern sky. This star is relatively close by at a distance of 17 light years from Earth. Intrinsically, it is about 10 times brighter than the Sun and spins around its axis in an exceptionally short period of about 10 hours. The Southern Cross is lying on its side, low in the south-west. The brightest star of the Cross is Acrux on the left or east of the constellation. This is made up of two hot stars that take over a thousand years to circle around each other. A spectrograph shows that one of these components is itself double, with its two stars racing around each other every 76 days. The Southern Cross can be used to find south. Extending a line through its main axis to the left or east, we reach Achernar, the brightest star in the constellation of Eridanus, the River. Halfway along the line is the South Celestial Pole (SCP), the point about which all the stars in the sky appear to circle every 24 hours. South is the point on the horizon directly below the SCP. DIARY FOR OCTOBER 2021

3

Sunday

Summer time begins (Australia)

2:00 am

6

Wednesday

New Moon

10:05 pm

13

Wednesday

First quarter

2:25 pm

21

Thursday

Full Moon

1:57 am

29

Friday

Last quarter

7:05 am

2021 AUSTRAL ASIAN SKY GUIDE

105

Evening twilight Mercury disappears, leaving Venus and the two giant planets, Jupiter and Saturn, to illuminate the evening sky. Mercury starts the month low in the west in Virgo but disappears into the twilight after three evenings. Venus is in the west. It starts the month in Libra, it moves into Scorpius at the start of the second week of the month, a week later it has a brief sojourn in Ophiuchus and, finally, another week later again into Ophiuchus. On 9 October the crescent Moon is below Venus, while the next evening it is above and to the right or north of the planet. On 17 October Venus passes the bright star Antares at a separation of three moon-widths. On 30 October Venus is at its maximum separation from the Sun and does not set for almost four hours after sunset. Jupiter is high in the north-east in Capricornus. On 15 October the gibbous Moon is above and to the right or east of Jupiter. Saturn is in the north, also in Capricornus. On 14 October the gibbous Moon is above and to the right or east of Saturn.

Morning twilight No morning planets. 8:00 pm on 10 October — Venus and the crescent Moon

106

2021 AUSTRAL ASIAN SKY GUIDE

Planets MERCURY Date

VENUS

MARS Set

JUPITER Rise

SATURN

Rise

Set

Rise

Set

Rise

Set

Rise

Set

1

6:04

19:17

7:33

21:37

5:43

18:06 14:13

3:43

12:56

2:52

2

5:59

19:10

7:33

21:39

5:41

18:06 14:08

3:39

12:52

2:48

3

6:54

20:03

8:32

22:40

6:39

19:05 15:04

4:35

13:48

3:44

4

6:48

19:55

8:32

22:42

6:36

19:04 15:00

4:31

13:44

3:40

5

6:43

19:46

8:31

22:44

6:34

19:03 14:56

4:27

13:40

3:36

6

6:37

19:37

8:31

22:45

6:32

19:02 14:52

4:23

13:36

3:32

7

6:31

19:28

8:31

22:47

6:30

19:02 14:48

4:19

13:32

3:29

8

6:25

19:18

8:30

22:49

6:27

19:01 14:44

4:15

13:28

3:25

6:19

19:08

8:30

22:50

6:25

19:00 14:39

4:11

13:24

3:21

6:14

18:58

8:30

22:52

6:23

18:59 14:35

4:07

13:20

3:17

11

6:08

18:48

8:29

22:53

6:21

18:58 14:31

4:03

13:16

3:13

12

6:02

18:39

8:29

22:55

6:19

18:58 14:27

3:59

13:12

3:09

13

5:57

18:30

8:29

22:56

6:16

18:57 14:23

3:55

13:08

3:05

14

5:52

18:22

8:29

22:58

6:14

18:56 14:19

3:51

13:04

3:01

15

5:48

18:15

8:29

22:59

6:12

18:55 14:15

3:47

13:00

2:57

16

5:43

18:08

8:29

23:01

6:10

18:54 14:11

3:43

12:57

2:53

17

5:40

18:02

8:29

23:02

6:08

18:54 14:07

3:39

12:53

2:49

18

5:36

17:57

8:29

23:04

6:05

18:53 14:03

3:35

12:49

2:45

19

5:33

17:53

8:28

23:05

6:03

18:52 13:59

3:31

12:45

2:41

20

5:30

17:50

8:28

23:06

6:01

18:51 13:56

3:27

12:41

2:38

21

5:28

17:48

8:29

23:07

5:59

18:51 13:52

3:23

12:37

2:34

22

5:26

17:46

8:29

23:09

5:57

18:50 13:48

3:19

12:33

2:30

23

5:24

17:46

8:29

23:10

5:55

18:49 13:44

3:15

12:29

2:26

24

5:23

17:45

8:29

23:11

5:53

18:48 13:40

3:11

12:26

2:22

25

5:22

17:46

8:29

23:12

5:50

18:48 13:36

3:07

12:22

2:18

26

5:21

17:47

8:29

23:13

5:48

18:47 13:32

3:03

12:18

2:14

27

5:20

17:48

8:29

23:14

5:46

18:46 13:29

3:00

12:14

2:10

28

5:19

17:50

8:29

23:15

5:44

18:46 13:25

2:56

12:10

2:07

29

5:19

17:53

8:30

23:16

5:42

18:45 13:21

2:52

12:07

2:03

30

5:18

17:55

8:30

23:16

5:40

18:44 13:17

2:48

12:03

1:59

31

5:18

17:58

8:30

23:17

5:38

18:43 13:14

2:44

11:59

1:55

2021 AUSTRAL ASIAN SKY GUIDE

107

OCT

9 10

Sun and twilight TWILIGHT START

OCT

Date

Day

SUN

TWILIGHT END

Nautical

Civil

Rise

Set

Civil

Nautical

1

Friday

4:38

5:08

5:33

17:58

18:23

18:52

2

Saturday

4:37

5:06

5:31

17:58

18:24

18:53

3

Sunday

5:35

6:05

6:30

18:59

19:24

19:54

4

Monday

5:34

6:03

6:29

19:00

19:25

19:55

5

Tuesday

5:33

6:02

6:27

19:01

19:26

19:55

6

Wednesday

5:31

6:01

6:26

19:01

19:27

19:56

7

Thursday

5:30

5:59

6:24

19:02

19:27

19:57

8

Friday

5:28

5:58

6:23

19:03

19:28

19:58

9

Saturday

5:27

5:57

6:22

19:04

19:29

19:59

10

Sunday

5:25

5:55

6:21

19:04

19:30

20:00

11

Monday

5:24

5:54

6:19

19:05

19:31

20:01

12

Tuesday

5:23

5:53

6:18

19:06

19:31

20:01

13

Wednesday

5:21

5:51

6:17

19:07

19:32

20:02

14

Thursday

5:20

5:50

6:15

19:08

19:33

20:03

15

Friday

5:19

5:49

6:14

19:08

19:34

20:04

16

Saturday

5:17

5:47

6:13

19:09

19:35

20:05

17

Sunday

5:16

5:46

6:12

19:10

19:36

20:06

18

Monday

5:14

5:45

6:10

19:11

19:37

20:07

19

Tuesday

5:13

5:44

6:09

19:12

19:37

20:08

20

Wednesday

5:12

5:42

6:08

19:13

19:38

20:09

21

Thursday

5:10

5:41

6:07

19:13

19:39

20:10

22

Friday

5:09

5:40

6:06

19:14

19:40

20:11

23

Saturday

5:08

5:39

6:05

19:15

19:41

20:12

24

Sunday

5:07

5:37

6:03

19:16

19:42

20:13

25

Monday

5:05

5:36

6:02

19:17

19:43

20:14

26

Tuesday

5:04

5:35

6:01

19:18

19:44

20:15

27

Wednesday

5:03

5:34

6:00

19:19

19:45

20:16

28

Thursday

5:02

5:33

5:59

19:19

19:46

20:17

29

Friday

5:00

5:32

5:58

19:20

19:47

20:18

30

Saturday

4:59

5:31

5:57

19:21

19:48

20:19

31

Sunday

4:58

5:30

5:56

19:22

19:49

20:20

108

2021 AUSTRAL ASIAN SKY GUIDE

Moon and tides MOON

TIMES AND HEIGHTS OF HIGH AND LOW WATERS Time

H (m)

Time

H (m)

Time

H (m)

Time

H (m)

Date

2:24 12:20

4:19

1.12

9:42

0.74

16:14

1.47

23:09

0.52

1

3:07 13:22

5:14

1.20

10:44

0.66

17:09

1.55

23:52

0.43

2

4:46 15:25

6:57

1.30

12:35

0.57

18:56

1.64

5:21 16:31

1:30

0.34

7:35

1.40

13:22

0.46

19:38

1.72

4

5:54 17:37

2:06

0.27

8:13

1.52

14:07

0.37

20:21

1.77

5

6:25 18:44

2:43

0.22

8:52

1.63

14:53

0.29

21:05

1.77

6

6:57 19:53

3:20

0.20

9:33

1.72

15:42

0.23

21:50

1.73

7

7:30 21:04

3:59

0.22

10:16

1.79

16:32

0.22

22:39

1.64

8

8:07 22:16

4:40

0.28

11:02

1.83

17:27

0.24

23:31

1.52

8:49 23:29

5:23

0.37

11:50

1.82

18:25

0.29

9:37

Rise

Set

3

9 10

0:28

1.39

6:11

0.48

12:44

1.77

19:31

0.36

11

10:33

0:39

1:31

1.27

7:07

0.58

13:44

1.70

20:45

0.42

12

11:35

1:42

2:46

1.19

8:14

0.66

14:54

1.63

22:03

0.44

13

12:40

2:37

4:10

1.19

9:33

0.69

16:11

1.60

23:13

0.42

14

13:46

3:24

5:21

1.24

10:51

0.66

17:22

1.61

14:51

4:03

0:10

0.39

6:17

1.32

11:58

0.59

18:20

1.62

16

15:53

4:37

0:57

0.36

7:03

1.41

12:55

0.52

19:10

1.63

17

16:53

5:07

1:36

0.34

7:44

1.50

13:43

0.46

19:53

1.62

18

17:52

5:34

2:11

0.34

8:21

1.56

14:26

0.42

20:31

1.58

19

18:49

6:01

2:42

0.36

8:56

1.61

15:05

0.40

21:09

1.53

20

19:47

6:28

3:11

0.39

9:29

1.65

15:44

0.40

21:45

1.47

21

20:44

6:56

3:40

0.43

10:00

1.67

16:21

0.41

22:21

1.40

22

21:42

7:26

4:08

0.48

10:33

1.67

17:00

0.43

22:58

1.33

23

22:40

8:00

4:38

0.54

11:06

1.66

17:40

0.46

23:38

1.27

24

23:36

8:39

5:11

0.60

11:43

1.62

18:23

0.51

15

25

0:21

1.20

5:48

0.66

12:23

1.57

19:13

0.56

26

1:11

1.15

6:34

0.72

13:11

1.51

20:11

0.60

27

1:18 11:08

2:12

1.11

7:32

0.77

14:08

1.46

21:18

0.60

28

2:02 12:06

3:24

1.12

8:44

0.79

15:15

1.45

22:23

0.57

29

2:42 13:08

4:35

1.17

10:00

0.76

16:24

1.47

23:17

0.51

30

3:18 14:11

5:31

1.26

11:07

0.69

17:25

1.53

31

Tidal predictions for Sydney only. Times are adjusted for daylight saving. © Commonwealth of Australia, Bureau of Meteorology, National Tidal Centre.

2021 AUSTRAL ASIAN SKY GUIDE

109

OCT

9:23 0:29 10:13

KEY







Bright Star

Faint Star Magellanic Cloud



V1 VENUS ON 7 NOVEMBER V2 VENUS ON 21 NOVEMBER

NOV

J JUPITER SATURN S

110

2021 AUSTRAL ASIAN SKY GUIDE

This sky map shows the ZODIAC CONSTELLATIONS, Non-Zodiac Constellations and Stars of the night sky as seen from Sydney at: 9:30 pm on 7 November 8:30 pm on 21 November For other dates subtract or add half an hour each week.

NOVEMBER 2021 The evening sky See sky map opposite Pegasus, the Winged Horse, is in the northern sky. This is the best time of the year to see this famous northern hemisphere constellation. Though it lacks bright stars, it is easily recognisable with the help of four stars outlining ‘the great square of Pegasus’. In the south-west Scorpius, the Scorpion, is disappearing below the horizon with only the stars of the tail visible. Over in the east Rigel, the brightest star in the constellation of Orion, the Hunter, is just rising above the horizon. This is the reverse of the situation earlier in the year in May, and again reflects the Scorpion’s perpetual chase of the giant Orion. Another star that is making a return to the evening sky this month is Canopus, the second-brightest star in the sky and the brightest star in the constellation of Carina, the Keel. Carina is one of three nautically themed constellations adjacent to each other in the sky. The other two, Vela, the Sails, and Puppis, the Stern, will be better seen next month. Together with Carina they made up the ancient constellation of Argo Navis, the Ship, before it was split. The Southern Cross is upside down in the south and so low in the sky that trees and houses easily block it from sight.

Partial eclipse of the Moon An almost total eclipse of the Moon takes place on the evening of Friday 19 November. From the North Island of New Zealand, it is visible in its entirety. For most Australian capital cities, except for Perth, the Moon rises already mostly in the Earth’s shadow (see page 10). DIARY FOR NOVEMBER 2021

5

Friday

New Moon

8:15 am

11

Thursday

First quarter

11:46 pm

19

Friday

Full Moon

7:57 pm

27

Saturday

Last quarter

11:28 pm

2021 AUSTRAL ASIAN SKY GUIDE

111

Evening twilight Venus and the two giant planets, Jupiter and Saturn, continue to grace the evening sky as they line up in the western sky. Venus is in the west, moving from Ophiuchus to Sagittarius at the beginning of the month. On 8 November the crescent Moon is above and to the right or north of Venus. Jupiter is high in the north-west in Capricornus. On 11 November the first quarter Moon is to the left or west of Jupiter, while the next evening the Moon, now gibbous, is above and to the right or north of the planet. Saturn is in the west, also in Capricornus. On 10 November the crescent Moon is to the left or south of Saturn.

Morning twilight No (major) planets. On 6 November there is a rare opportunity to easily find the minor planet (1) Ceres with binoculars as it is very close to the bright star Aldebaran in the north-west.

9:00 pm on 30 November — three planets

112

2021 AUSTRAL ASIAN SKY GUIDE

Planets MERCURY Date

VENUS

MARS Set

JUPITER Rise

SATURN

Rise

Set

Rise

Set

Rise

Set

Rise

Set

1

5:18

18:01

8:30

23:18

5:36

18:43 13:10

2:40

11:55

1:51

2

5:18

18:04

8:31

23:18

5:34

18:42 13:06

2:37

11:52

1:48

3

5:18

18:08

8:31

23:19

5:32

18:41 13:03

2:33

11:48

1:44

4

5:18

18:11

8:31

23:19

5:30

18:41 12:59

2:29

11:44

1:40

5

5:18

18:15

8:31

23:20

5:28

18:40 12:55

2:25

11:40

1:36

6

5:18

18:19

8:32

23:20

5:25

18:39 12:52

2:21

11:37

1:32

7

5:19

18:22

8:32

23:20

5:23

18:39 12:48

2:18

11:33

1:28

8

5:19

18:26

8:32

23:21

5:21

18:38 12:44

2:14

11:29

1:25

9

5:19

18:30

8:33

23:21

5:19

18:37 12:41

2:10

11:25

1:21

10

5:20

18:34

8:33

23:21

5:17

18:37 12:37

2:06

11:22

1:17

11

5:20

18:38

8:33

23:21

5:15

18:36 12:34

2:03

11:18

1:13

12

5:20

18:42

8:33

23:20

5:14

18:35 12:30

1:59

11:14

1:10

13

5:21

18:46

8:34

23:20

5:12

18:35 12:27

1:55

11:11

1:06

14

5:21

18:50

8:34

23:20

5:10

18:34 12:23

1:52

11:07

1:02

15

5:22

18:54

8:34

23:20

5:08

18:33 12:20

1:48

11:03

0:58

16

5:23

18:58

8:34

23:19

5:06

18:33 12:16

1:44

11:00

0:55

17

5:23

19:02

8:34

23:18

5:04

18:32 12:13

1:41

10:56

0:51

18

5:24

19:06

8:34

23:18

5:02

18:32 12:09

1:37

10:52

0:47

19

5:25

19:10

8:34

23:17

5:00

18:31 12:06

1:33

10:49

0:43

20

5:25

19:14

8:34

23:16

4:58

18:30 12:02

1:30

10:45

0:40

21

5:26

19:19

8:34

23:15

4:56

18:30 11:59

1:26

10:42

0:36

22

5:27

19:23

8:34

23:14

4:54

18:29 11:55

1:22

10:38

0:32

23

5:28

19:27

8:34

23:13

4:53

18:28 11:52

1:19

10:34

0:28

24

5:29

19:31

8:34

23:12

4:51

18:28 11:49

1:15

10:31

0:25

25

5:30

19:35

8:33

23:10

4:49

18:27 11:45

1:11

10:27

0:21

26

5:32

19:39

8:33

23:09

4:47

18:27 11:42

1:08

10:24

0:17

27

5:33

19:42

8:33

23:07

4:45

18:26 11:39

1:04

10:20

0:14

28

5:34

19:46

8:32

23:06

4:44

18:26 11:35

1:01

10:16

0:10

29

5:36

19:50

8:32

23:04

4:42

18:25 11:32

0:57

10:13

0:06

30

5:37

19:54

8:31

23:02

4:40

18:24 11:29

0:54

10:09

0:03 23:59

NOV

2021 AUSTRAL ASIAN SKY GUIDE

113

Sun and twilight TWILIGHT START Date

Day

SUN

TWILIGHT END

Nautical

Civil

Rise

Set

Civil

Nautical

1

Monday

4:57

5:29

5:55

19:23

19:50

20:21

2

Tuesday

4:56

5:28

5:54

19:24

19:51

20:22

3

Wednesday

4:55

5:27

5:53

19:25

19:52

20:24

4

Thursday

4:54

5:26

5:52

19:26

19:53

20:25

5

Friday

4:53

5:25

5:51

19:27

19:54

20:26

6

Saturday

4:51

5:24

5:50

19:28

19:55

20:27

7

Sunday

4:50

5:23

5:50

19:29

19:56

20:28

8

Monday

4:49

5:22

5:49

19:30

19:57

20:29

9

4:48

5:21

5:48

19:31

19:58

20:30

Wednesday

4:47

5:20

5:47

19:31

19:59

20:31

11

Thursday

4:47

5:19

5:46

19:32

20:00

20:33

12

Friday

4:46

5:18

5:46

19:33

20:01

20:34

13

Saturday

4:45

5:18

5:45

19:34

20:02

20:35

14

Sunday

4:44

5:17

5:44

19:35

20:03

20:36

15

Monday

4:43

5:16

5:44

19:36

20:04

20:37

16

Tuesday

4:42

5:16

5:43

19:37

20:05

20:38

17

Wednesday

4:42

5:15

5:42

19:38

20:06

20:39

18

Thursday

4:41

5:14

5:42

19:39

20:07

20:41

19

Friday

4:40

5:14

5:41

19:40

20:08

20:42

20

Saturday

4:39

5:13

5:41

19:41

20:09

20:43

21

Sunday

4:39

5:13

5:40

19:42

20:10

20:44

22

Monday

4:38

5:12

5:40

19:43

20:11

20:45

23

Tuesday

4:37

5:12

5:40

19:44

20:12

20:46

24

Wednesday

4:37

5:11

5:39

19:45

20:13

20:47

25

Thursday

4:36

5:11

5:39

19:46

20:14

20:48

26

Friday

4:36

5:10

5:38

19:47

20:15

20:49

27

Saturday

4:35

5:10

5:38

19:48

20:16

20:51

28

Sunday

4:35

5:10

5:38

19:49

20:17

20:52

29

Monday

4:35

5:09

5:38

19:49

20:18

20:53

30

Tuesday

4:34

5:09

5:38

19:50

20:19

20:54

NOV

Tuesday

10

114

2021 AUSTRAL ASIAN SKY GUIDE

Moon and tides MOON

TIMES AND HEIGHTS OF HIGH AND LOW WATERS Time

H (m)

Time

H (m)

Time

H (m)

Time

H (m)

Date

3:50 15:15

0:03

0.43

6:16

1.38

12:04

0.59

18:16

1.60

1

4:22 16:21

0:44

0.35

6:59

1.51

12:58

0.47

19:05

1.65

2

4:53 17:29

1:23

0.29

7:40

1.65

13:48

0.36

19:53

1.67

3

5:25 18:39

2:03

0.25

8:22

1.78

14:39

0.26

20:42

1.66

4

6:00 19:53

2:44

0.26

9:06

1.89

15:30

0.19

21:33

1.61

5

6:40 21:08

3:27

0.29

9:52

1.96

16:25

0.17

22:27

1.53

6

7:27 22:22

4:12

0.36

10:42

1.97

17:21

0.18

23:23

1.43

7

8:21 23:31

5:00

0.45

11:32

1.94

18:20

0.24

9:23

Rise

Set

8

0:23

1.34

5:54

0.54

12:28

1.87

19:25

0.31

9

10:30

0:32

1:28

1.27

6:54

0.62

13:28

1.76

20:33

0.37

10

11:38

1:23

2:39

1.24

8:02

0.68

14:34

1.66

21:40

0.41

11

12:44

2:05

3:51

1.25

9:18

0.71

15:46

1.58

22:41

0.44

12

13:47

2:40

4:55

1.31

10:32

0.69

16:54

1.53

23:32

0.44

13

14:48

3:11

5:48

1.39

11:40

0.64

17:51

1.50

15:46

3:39

0:16

0.44

6:33

1.47

12:39

0.59

18:41

1.47

15

16:43

4:05

0:55

0.44

7:14

1.55

13:29

0.53

19:25

1.45

16

17:40

4:31

1:29

0.44

7:51

1.62

14:12

0.48

20:05

1.42

17

18:37

4:58

2:00

0.46

8:25

1.68

14:51

0.45

20:44

1.39

18

19:34

5:28

2:30

0.48

8:58

1.72

15:28

0.42

21:21

1.36

19

20:32

6:00

3:00

0.51

9:30

1.74

16:04

0.41

22:00

1.33

20

21:29

6:38

3:32

0.54

10:04

1.75

16:42

0.41

22:38

1.29

21

22:23

7:20

4:07

0.58

10:40

1.73

17:21

0.44

23:18

1.26

22

23:14

8:07

4:44

0.63

11:16

1.70

18:02

0.47

9:00

0:01

1.22

5:24

0.67

11:57

1.65

18:48

0.51

24

9:57

0:48

1.19

6:10

0.72

12:42

1.60

19:38

0.54

25

0:40 10:56

1:43

1.17

7:02

0.75

13:31

1.55

20:33

0.55

26

1:16 11:57

2:43

1.19

8:05

0.77

14:30

1.51

21:30

0.53

27

1:49 12:59

3:46

1.24

9:15

0.76

15:32

1.49

22:23

0.48

28

2:20 14:02

4:44

1.34

10:26

0.70

16:37

1.50

23:11

0.43

29

2:49 15:06

5:34

1.46

11:32

0.61

17:37

1.52

23:57

0.38

30

0:00

14

23

Tidal predictions for Sydney only. Times are adjusted for daylight saving.

2021 AUSTRAL ASIAN SKY GUIDE

NOV

© Commonwealth of Australia, Bureau of Meteorology, National Tidal Centre.

115

KEY







Bright Star

Faint Star Magellanic Cloud



V1 VENUS ON 7 DECEMBER V2 VENUS ON 21 DECEMBER

J JUPITER

DEC

SATURN S

116

2021 AUSTRAL ASIAN SKY GUIDE

This sky map shows the ZODIAC CONSTELLATIONS, Non-Zodiac Constellations and Stars of the night sky as seen from Sydney at: 10:30 pm on 7 December 9:30 pm on 21 December For other dates subtract or add half an hour each week.

DECEMBER 2021 The evening sky See sky map opposite The summer constellation of Orion, the Hunter, is high in the northeast. The three stars in the middle of the constellation represent the belt of Orion. Above and a little further to the right or east of the rightmost star of the belt, we find a line of three faint objects, which make up the dagger or sword of Orion. In the middle is one of the most famous sights in the sky, the Great Nebula in Orion. Extending a line through the stars of the belt towards the right or east, we reach Sirius, the brightest star in the sky. Extending the line in the other direction, we find Aldebaran, the orange-coloured brightest star in the constellation of Taurus, the Bull.

Partial eclipse of the Sun This shallow eclipse is only visible from Hobart and Melbourne. It begins on Saturday 4 December at 7:34 pm AEDT in Hobart and at 7:53 pm in Melbourne. From Hobart, at its maximum the eclipse covers 21 per cent of the Sun’s width, while from Melbourne it covers only 7 per cent. From both cities the eclipse ends at sunset. Always take precautions when looking at the Sun, even when it is low in the sky.

Meteor shower The Geminids are one of the year’s best meteor showers seen from the Southern Hemisphere. There is an exceptionally good window of time to view the meteors without the Moon brightening the sky on Tuesday 14 and Wednesday 15 December. Look north after moonset in the early morning (see page 11). DIARY FOR DECEMBER 2021

4

Saturday

New Moon

6:43 pm

11

Saturday

First quarter

12:36 pm

19

Sunday

Full Moon

3:35 pm

22

Wednesday

Summer solstice

2:59 am

27

Monday

Last quarter

1:24 pm

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Evening twilight Mercury joins Venus, Jupiter and Saturn as an evening planet. Mercury appears low in the south-west in Sagittarius during the last week of the month. On 27 December Venus is to the right or west of Mercury. Venus is low in the west in Sagittarius. On 7 December the crescent Moon is above and to the right or north of Venus. Jupiter is in the west, moving from Capricornus to Aquarius in the middle of the month. On 9 December the crescent Moon is above and to the left or south of Jupiter. Saturn is in the west in Capricornus. On 8 December the crescent Moon is above Saturn.

Morning twilight Mars appears low in the east in Libra late in the first week of December but moves into Scorpius in the middle of the month and then into Ophiuchus for the last week.

9:00 pm on 8 December — three planets and the crescent Moon

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Planets MERCURY Date

VENUS

MARS Set

JUPITER Rise

Set

SATURN

Rise

Set

Rise

Set

Rise

1

5:39

19:58

8:30

23:00

4:38

18:24 11:25

0:50 10:06 23:55

Rise

Set

2

5:40

20:02

8:29

22:58

4:37

18:23 11:22

0:46 10:02 23:52

3

5:42

20:06

8:28

22:55

4:35

18:23 11:19

0:43

9:59 23:48

4

5:44

20:09

8:27

22:53

4:33

18:22 11:16

0:39

9:55 23:44

5

5:46

20:13

8:26

22:50

4:31

18:22 11:12

0:36

9:52 23:41

6

5:48

20:17

8:25

22:48

4:30

18:21 11:09

0:32

9:48 23:37

7

5:50

20:20

8:23

22:45

4:28

18:20 11:06

0:29

9:45 23:33

8

5:52

20:24

8:22

22:42

4:27

18:20 11:03

0:25

9:41 23:30

9

5:54

20:27

8:20

22:39

4:25

18:19 10:59

0:22

9:38 23:26

10

5:57

20:31

8:19

22:36

4:23

18:19 10:56

0:18

9:34 23:22

11

5:59

20:34

8:17

22:32

4:22

18:18 10:53

0:15

9:31 23:19

12

6:02

20:38

8:15

22:29

4:20

18:18 10:50

0:11

9:27 23:15

13

6:05

20:41

8:12

22:25

4:19

18:17 10:47

0:08

9:24 23:11

14

6:07

20:44

8:10

22:21

4:17

18:17 10:44

0:04

9:20 23:08

15

6:10

20:47

8:07

22:17

4:15

18:16 10:40

0:01

9:17 23:04

23:57 16

6:13

20:50

8:05

22:13

4:14

18:16 10:37 23:54

9:13 23:00

17

6:16

20:53

8:02

22:08

4:12

18:15 10:34 23:50

9:10 22:57

18

6:19

20:56

7:59

22:04

4:11

18:14 10:31 23:47

9:06 22:53

19

6:23

20:59

7:55

21:59

4:10

18:14 10:28 23:44

9:03 22:50

20

6:26

21:02

7:52

21:54

4:08

18:13 10:25 23:40

8:59 22:46

21

6:29

21:04

7:48

21:49

4:07

18:13 10:22 23:37

8:56 22:42

22

6:33

21:07

7:45

21:44

4:05

18:12 10:19 23:33

8:52 22:39

23

6:36

21:09

7:41

21:39

4:04

18:12 10:16 23:30

8:49 22:35

24

6:40

21:11

7:37

21:33

4:02

18:11 10:13 23:26

8:46 22:32

25

6:43

21:13

7:32

21:27

4:01

18:11 10:10 23:23

8:42 22:28

26

6:47

21:15

7:28

21:22

4:00

18:10 10:07 23:20

8:39 22:24

27

6:50

21:17

7:23

21:16

3:58

18:10 10:04 23:16

8:35 22:21

28

6:54

21:18

7:18

21:09

3:57

18:09 10:00 23:13

8:32 22:17

29

6:58

21:20

7:13

21:03

3:56

18:08

9:57 23:09

8:28 22:14

30

7:01

21:21

7:08

20:57

3:55

18:08

9:54 23:06

8:25 22:10

31

7:05

21:22

7:03

20:50

3:53

18:07

9:51 23:03

8:22 22:06

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Sun and twilight TWILIGHT START

DEC

Date

SUN

TWILIGHT END

Day

Nautical

Civil

Rise

Set

Civil

Nautical

1

Wednesday

4:34

5:09

5:37

19:51

20:20

20:55

2

Thursday

4:34

5:09

5:37

19:52

20:21

20:56

3

Friday

4:33

5:09

5:37

19:53

20:22

20:57

4

Saturday

4:33

5:08

5:37

19:54

20:22

20:58

5

Sunday

4:33

5:08

5:37

19:55

20:23

20:59

6

Monday

4:33

5:08

5:37

19:55

20:24

21:00

7

Tuesday

4:33

5:08

5:37

19:56

20:25

21:00

8

Wednesday

4:33

5:08

5:37

19:57

20:26

21:01

9

Thursday

4:33

5:08

5:37

19:58

20:27

21:02

10

Friday

4:33

5:08

5:37

19:59

20:28

21:03

11

Saturday

4:33

5:09

5:38

19:59

20:28

21:04

12

Sunday

4:33

5:09

5:38

20:00

20:29

21:05

13

Monday

4:33

5:09

5:38

20:01

20:30

21:05

14

Tuesday

4:33

5:09

5:38

20:01

20:30

21:06

15

Wednesday

4:34

5:09

5:38

20:02

20:31

21:07

16

Thursday

4:34

5:10

5:39

20:03

20:32

21:08

17

Friday

4:34

5:10

5:39

20:03

20:32

21:08

18

Saturday

4:35

5:10

5:39

20:04

20:33

21:09

19

Sunday

4:35

5:11

5:40

20:04

20:34

21:09

20

Monday

4:35

5:11

5:40

20:05

20:34

21:10

21

Tuesday

4:36

5:12

5:41

20:06

20:35

21:11

22

Wednesday

4:36

5:12

5:41

20:06

20:35

21:11

23

Thursday

4:37

5:13

5:42

20:06

20:36

21:11

24

Friday

4:37

5:13

5:42

20:07

20:36

21:12

25

Saturday

4:38

5:14

5:43

20:07

20:36

21:12

26

Sunday

4:38

5:14

5:43

20:08

20:37

21:13

27

Monday

4:39

5:15

5:44

20:08

20:37

21:13

28

Tuesday

4:40

5:16

5:45

20:08

20:37

21:13

29

Wednesday

4:41

5:16

5:45

20:09

20:38

21:13

30

Thursday

4:41

5:17

5:46

20:09

20:38

21:14

31

Friday

4:42

5:18

5:47

20:09

20:38

21:14

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Moon and tides MOON Rise

TIMES AND HEIGHTS OF HIGH AND LOW WATERS

Set

Time

H (m)

Date

Time

H (m)

Time

H (m)

Time

H (m)

3:20 16:13

6:21

1.61

12:34

0.49

18:34

1.54

3:52 17:24

0:42

0.34

7:08

1.75

13:32

0.37

19:30

1.54

2

4:29 18:38

1:27

0.33

7:56

1.89

14:28

0.26

20:25

1.52

3

5:12 19:54

2:13

0.34

8:45

1.99

15:23

0.18

21:20

1.49

4

6:03 21:09

3:01

0.37

9:34

2.05

16:18

0.14

22:17

1.45

5

7:04 22:16

3:52

0.41

10:27

2.06

17:14

0.15

23:15

1.40

6

8:11 23:14

4:45

0.47

11:19

2.01

18:11

0.20

9:21

0:13

1.35

5:41

0.54

12:14

1.92

19:08

0.27

1

7 8

10:31

0:01

1:12

1.32

6:40

0.60

13:09

1.80

20:06

0.35

9

11:37

0:40

2:14

1.30

7:43

0.66

14:07

1.66

21:02

0.42

10

12:40

1:13

3:15

1.32

8:50

0.70

15:08

1.54

21:55

0.47

11

13:40

1:42

4:14

1.36

10:00

0.72

16:11

1.43

22:44

0.51

12

14:38

2:09

5:08

1.42

11:11

0.70

17:11

1.36

23:28

0.52

13

15:34

2:35

5:56

1.49

12:15

0.66

18:05

1.32

16:31

3:02

0:07

0.53

6:40

1.56

13:10

0.61

18:55

1.29

15

17:28

3:30

0:45

0.54

7:19

1.63

13:56

0.54

19:41

1.29

16

18:25

4:02

1:22

0.54

7:56

1.69

14:36

0.49

20:23

1.29

17

19:23

4:37

1:58

0.55

8:32

1.73

15:14

0.44

21:03

1.29

18

20:18

5:18

2:33

0.56

9:08

1.76

15:50

0.41

21:43

1.29

19

21:10

6:04

3:10

0.57

9:44

1.78

16:27

0.40

22:21

1.28

20

21:58

6:55

3:46

0.58

10:20

1.78

17:03

0.41

23:00

1.27

21

22:40

7:51

4:26

0.60

10:59

1.76

17:43

0.43

23:40

1.26

22

23:17

8:50

5:06

0.62

11:37

1.73

18:23

0.45

23:51

14

23

9:50

0:23

1.25

5:50

0.65

12:18

1.68

19:06

0.46

24

10:50

1:11

1.26

6:40

0.68

13:02

1.62

19:51

0.47

25

0:21 11:51

2:03

1.28

7:35

0.70

13:52

1.56

20:39

0.47

26

0:50 12:53

3:00

1.33

8:40

0.71

14:49

1.49

21:30

0.47

27

1:19 13:56

3:57

1.42

9:51

0.68

15:54

1.44

22:21

0.46

28

1:49 15:02

4:53

1.53

11:06

0.62

17:03

1.41

23:14

0.45

29

2:22 16:12

5:48

1.66

12:17

0.51

18:11

1.39

3:00 17:25

0:06

0.43

6:42

1.79

13:22

0.38

19:15

1.40

30 31

Tidal predictions for Sydney only. Times are adjusted for daylight saving. © Commonwealth of Australia, Bureau of Meteorology, National Tidal Centre.

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FURTHER INFORMATION There are many ways to find out more about the fascinating subject of planets, space exploration, stars, constellations and the origins of life and the universe. Books and magazines give in-depth information, while websites are regularly updated. The latest news can often be found on astronomers’ accounts in Twitter, such as Katie Mack’s @AstroKatie and Neil deGrasse Tyson’s @neiltyson.

Books • Fred Watson, Cosmic Chronicles: A User's Guide to the Universe, NewSouth, Sydney, 2019. The popular astronomer and author brings you up-to-date with the mysteries of space and the sky in his unique entertaining fashion. • Katie Mack, The End of Everything (Astrophysically Speaking), Allen Lane, London, 2020. The well-known Australian astrophysicist and tweeter writes about the various possibilities for the end of the Universe; an end we cannot prevent but at least we can understand. • Katie Coppens and Grant Tremblay, What Do Black Holes Eat for Dinner?, Tumblehome Learning, Inc, Pembroke, 2020. A teacher and an astrophysicist provide answers to numerous commonly asked questions about space and astronomy.

Magazines • Australian Sky & Telescope, Odysseus Publishing. Articles on astronomy for all skywatchers. Available online at skyandtelescope.com.au

Websites • https://skyandtelescope.org/astronomynews/ — the latest news in space from the best-known popular astronomy magazine. • https://maas.museum/observations/ — a blog with interesting information on astronomy with an emphasis on the Southern Hemisphere. • http://astroblogger.blogspot.com/ — an astronomy blog from an Adelaide biologist and amateur astronomer.

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Travel poster for a future visit to Saturn’s moon Titan, a moon resembling the primordial Earth but with rivers, lakes and seas, such as Kraken Mare, of liquid ethane and methane. Courtesy NASA/JPL-Caltech

AMATEUR ASTRONOMICAL SOCIETIES

Amateur astronomers setting up their telescopes for a night’s observing at a star party. Courtesy Russell Cockman

There are amateur societies all over Australia and New Zealand. Here is a list: • Sydney City Skywatchers — sydneycityskywatchers.org • Astronomical Society of NSW — asnsw.com • Northern Sydney Astronomical Society — nsas.org.au • Sutherland Astronomical Society — sasi.net.au • Western Sydney Amateur Astronomy Group — wsaag.org • Sydney Outdoor Lighting Improvement Society — solis.asn.au • Astronomical Society of Victoria — asv.org.au • Mornington Peninsula Astronomical Society — mpas.asn.au • Mount Burnett Observatory — mbo.org.au • International Dark-Sky Association of Victoria — darkskyvic.org • Astronomical Society of South Australia — assa.org.au • Brisbane Astronomical Society — bas.asn.au • Astronomical Society of Western Australia — aswa-inc.org.au • Auckland Astronomical Society — astronomy.org.nz • Canterbury Astronomical Society — cas.org.nz • Wellington Astronomical society — was.org.nz • Australian Dark Sky Alliance — australasiandarkskyalliance.org

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OBSERVATORIES AND PLANETARIUMS Observatories and planetariums are great places to visit to connect with the sky. In addition to daytime activities, night-time events in observatories allow visitors to view the planets and some of the most spectacular objects in the sky through telescopes. In recent years planetariums have become even more exciting places to visit with their new projection technology.

Sydney Observatory The oldest observatory in Australia offers a range of experiences, including exhibitions on astronomy and meteorology, a Space Theatre, a digital planetarium and night telescope viewings. The telescope and dome in the grounds are accessible for people in wheelchairs. 1003 Upper Fort Street, Millers Point maas.museum/sydney-observatory/ Enquiries/bookings: (02) 9217 0111 or [email protected]

Other places • Sir Thomas Brisbane Planetarium — brisbane.qld.gov.au/thingsto-see-and-do/council-venues-and-precincts/sir-thomasbrisbane-planetarium • Melbourne Planetarium, Scienceworks — museumsvictoria.com.au/ scienceworks/visiting/melbourne-planetarium • Adelaide Planetarium — unisa.edu.au/planetarium • Scitech Planetarium, Perth — scitech.org.au/experience/ planetarium/ • Perth Observatory — perthobservatory.com.au • Space Place, Wellington — museumswellington.org.nz/spaceplace • Stardome Observatory and Planetarium, Auckland — stardome.org.nz

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The iconic 50-cm Edith Winstone Blackwell Zeiss Telescope at Stardome Observatory and Planetarium, Auckland. Photo Nick Lomb

GLOSSARY aphelion: the time when a planet or another object circling the Sun is at its furthest distance from it. apogee: the time when the Moon is at its furthest point from the Earth in its oval-shaped monthly path around it. big bang theory: the most widely accepted theory of the origin of the universe which claims that it originated in an extremely hot dense form 13.8 billion years ago and has been expanding since then. black hole: an object with such a strong gravitational pull that nothing, not even light, can escape from it. It is believed that the collapse of a very massive star could cause a black hole. blue Moon: the second full Moon in a calendar month. captured asteroid: an asteroid that has been forced to circle a more massive body, such as a planet, with a greater gravitational pull. comet: a small mass of ice and rock circling the Sun in an elongated path. When close to the Sun, some of the ice in the outer layers turns to gas. This gas, together with dust that was mixed in with ice, forms a huge cloud around the original body. conjunction: when two or more celestial objects at different distances from the Earth, such as planets or the Moon, appear close together in the sky. constellation: a group of stars that look like they make up a pattern. dark matter: there is more matter in the universe than we can see; possibly as much as 100 times more. Dark matter could be cold — made of particles or objects moving much slower than the speed of light. It could be hot, made of particles such as neutrinos, which move close to the speed of light. dwarf planet: an object circling the Sun that is sufficiently massive for gravity to pull it into a roughly spherical shape, but has other objects of similar size moving in roughly the same path. eclipse: there are two main types of eclipses: solar and lunar. In a solar eclipse, the Moon moves in front of the Sun and blocks it from view, partially or fully. In a lunar eclipse, the shadow of the Earth falls on the Moon, either partially or fully covering it. ecliptic: the apparent path followed by the Sun across the sky each year. The planets are always found near this line. equinox: twice in the year when the Sun crosses the Earth’s equator.

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galaxy: a large collection of stars, dust and gas. Our galaxy is the Milky Way, which consists of about 200 billion stars and is about 100,000 light years across. light year: the distance travelled by light in one year. As light travels at 300,000 km per second, this is the very large distance of 9.5 million million km. magnetic field: an invisible field created by a magnet or moving electric charges. In turn, the field can exert magnetic force on objects such as those made of iron or materials containing moving electrical charges, such as charged gases or plasmas. meteor: the streak of light produced as a small dust particle hits the Earth’s atmosphere and burns up. Generally, the particle is smaller than a pea. Meteors are colloquially known as ‘falling stars’. meteorite: a piece of rock from space that has survived its passage through the Earth’s atmosphere and reached the ground. meteor shower: when a stream of dust particles shredded by a comet, such as Halley's Comet, hits the Earth. Observers can see larger than usual numbers of meteors, which appear to be coming from a particular point in the sky called the radiant. Moon illusion: a psychological effect where the Moon appears larger and closer when it is near the horizon than when it is high in the sky. moonset: this occurs when the top edge of the Moon has disappeared below the horizon. nebula: a cloud of gas and dust. It could be a place where stars are forming, or it could be a remnant of a star that exploded (a supernova). occultation: when the Moon or a planet covers another object, such as a planet, an asteroid or a star, for a brief period. orbit: the path a planet takes under the gravitational pull of a star or the path a moon takes under the gravitational pull of a planet. periastron: when a celestial body is in the part of its path that passes closest to the star (other than the Sun) that it is circling. perigee: the time when the Moon is at its closest point to Earth in its oval-shaped monthly path around it. The term can also apply to artificial satellites circling the Earth. perihelion: when a planet or another solar system body such as a comet is in the part of its path that passes closest to the Sun.

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planet: an object that is circling around a star and is too small to be able to generate its own energy by nuclear reactions. A planet is sufficiently massive for its gravity to pull itself into a roughly spherical shape, and ‘has cleared its orbit’; that is, there are no comparable sized objects circling the Sun in the same path. prograde: when a moon circles a planet in the direction of the planet’s spin. red giant: a star near the end of its life that has expanded to many times its original size. Although still very bright, its energy is spread out over an enormous outer surface, and so it appears cool and red. red shift: the universe has become bigger since light left the distant objects that we see. This means the light waves from distant objects are stretched out to longer or redder wavelengths. resonance: when two moons or two planets have periods that are related by a simple ratio, such as 3:1 or 2:3, they can exert a regular gravitational influence on each other. retrograde: when a moon circles a planet in the opposite direction to the planet’s spin. short-period comet: a comet that moves around the Sun in less than 200 years, or one that has been observed at more than one perihelion passage. solstice: when the Sun is at its highest or lowest point in the sky for the year at midday. star: a large sphere of gas that creates energy by nuclear reactions in its central regions. supermoon: the appearance of the Moon when the time of full Moon is close to the time of perigee. supernova: a massive star that explodes at the end of its life. For a short time, the exploding star can shine brighter than a galaxy of 10 billion stars. terminator: the line dividing the lit part of the Moon’s visible disc from the unlit part. white dwarf: the remains of a dying star. A white dwarf is extremely dense; a matchbox full of its material would need up to 30 strong people to lift! zodiac: the 13 constellations through which the Sun appears to travel each year.

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THE STORY OF SYDNEY OBSERVATORY Explore the rich history of one of Australia’s oldest astronomical landmarks. Using archival images and objects from the Museum of Applied Arts and Sciences collection, The Story of Sydney Observatory details the evolution of the astronomical observatory to a working museum. From the close cultural relationship shared between a colonial lieutenant and a Gadigal woman to the Melbourne astrograph telescope used to map the stars of the Milky Way galaxy, the stories inside shed light on the site, people and objects that have helped to shape Sydney Observatory into what it is today. Featuring a range of authors, including award-winning writer Bruce Pascoe and astronomer Nick Lomb.

Available from Sydney Observatory, the MAAS Store, selected bookstores in Australia and New Zealand and online at maas.museum/store RRP $10.

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2021 AUSTRALASIAN SKY GUIDE EBOOK This book is available for download with iBooks on your Mac or iOS device, and with iTunes on your computer. Books can be read with iBooks on your Mac or iOS device. It is also available as an eBook from amazon.com.au. About the cover image Comet SWAN (C/2020 F8) This spectacular photograph of Comet SWAN by Ross Giakoumatos was selected as the winner of the 2020 Australasian Sky Guide Cover Award, which is awarded by the Central West Astronomical Society as part of the annual David Malin Awards (see page 41). It also received an Honourable Mention in the Solar System category. The comet was photographed from suburban Sydney, low in the eastern sky only a couple of hours before sunrise, using a 102 mm refractor (lens) telescope. Photo courtesy Ross Giakoumatos

About the author Dr Nick Lomb spent over 30 years at Sydney Observatory. He curated numerous exhibitions and was a frequent commentator on astronomical events in the southern sky. He is an adjunct professor at the University of Southern Queensland and researches the history of Australian astronomy. Nick was a regular contributor to the Observatory’s blog and has been the author of the annual Sky Guide since 1991. He has authored and co-authored several other books, including Transit of Venus: 1631 to the Present, as well as numerous research papers.