Total eclipses of the Sun from Australia

Total eclipse of the Sun as seen from Woomera, South Australia on 4 December 2002. Picture and copyright Nick Lomb ©, all rights reserved

Total eclipses of the Sun are probably the most spectacular events in Nature. During the day the sky becomes dark, birds and animals become confused and suddenly the faint outer atmosphere of the Sun, the corona, snaps into view. Many avid eclipse watchers travel great distances to have the opportunity of seeing such a wonderful event. Among these keen eclipse watchers is the Sydney Observatory group that travelled to Easter Island earlier in 2010.

There are occasionally opportunities to view total eclipses of the Sun closer to home, from the Australian continent. Here we mention some past and some forthcoming ones.

A total eclipse was to be seen from Sydney soon after the arrival of the first Government Astronomer for NSW, Rev William Scott. The eclipse took place on 25 March 1857 in the early morning at around 6:47 am in present day AEST and lasted just under two minutes. Sensibly Scott travelled out to South Head light house so as to observe the event over the ocean as the Sun was only about eight degrees above the horizon. Unfortunately, the sky was totally covered by cloud and poor Rev Scott saw nothing.

A much later eclipse that is still remembered by older astronomers is the one that passed over Melbourne on 23 October 1976. The eclipse took place in the late afternoon and lasted two and a half minutes. Many astronomers from Sydney travelled to the town of Bombala in the south of NSW and near the Victorian border to view the event. On the day there were patchy clouds and most observers missed the event though others nearby had a good view.

A later eclipse occurred on 4 December 2002 with the track of the eclipse passing through parts of South Australia. Many groups of amateur and professional astronomers travelled to Ceduna for the event. I led a Sydney Observatory group together with space expert Kerrie Dougherty from the Powerhouse Museum. We did not go Ceduna, but took the opportunity to visit the Woomera rocket range as that also on the track of the eclipse. The eclipse took place in the late afternoon with the Sun already near the horizon and lasted just under 30 seconds. From Woomera the sky was completely clear and we had a wonderful view as illustrated in the photograph above. Those who travelled to Ceduna also saw the eclipse in between clouds that cleared only at the last second.

The next eclipse to be seen from Australia will take place on 14 November 2012 and will be best seen from Cairns in North Queensland. It will be in the early morning with the Sun very low on the horizon so the possibility of clouds has to be considered. Once again there will be the opportunity to join a Sydney Observatory tour group and details will soon be available on the Observatory website. In the meantime I have prepared a factsheet with full information on the event for the Astronomical Society of Australia.

For those from Sydney who do not want to travel and have the patience to wait there will be a total eclipse visible from Sydney on 22 July 2028. It should be an excellent eclipse occurring in the middle of the day with the Sun high in the sky and lasting for almost four minutes. Let us hope that the clouds will be kinder than they were for Rev Scott back in 1857!

2010 Sydney Observatory Eclipse Trip: Eclipse Day

Melissa, Toner and Lilly on Rapa Nui preparing for the 2010 total solar eclipse. Photo Andrew Jacob

At 3am on July 11, 2010 we were all disturbed in our sleep by incoming aeroplanes carrying more eclipse viewers. The wind was howling, rain was lashing at the tents. At 6:30am there was a cry from Lilly ‘Get up, get up! There are stars, I can see Pleiades!” After 2 days of rain and cloud the sky was clearing, however, the occasional shower and a howling wind persisted.

At 9am we piled into the bus, raincoats, warm weather gear at hand to Tahai. The National Parks had given us special permission to erect a basecamp tent next to the Park Ranger’s hut.

There are three Ahus at this site and we mainly setup our tripods in the viewing area in front of the imposing Ahu Tahai, looking topwards Ahu Ko Te Riku, the Moai with eyes.

There were about 1,000 other eclipse viewers, stalls selling local crafts, and a traditional dance group. People had come from North America, Italy, France, Germany, the UK, Japan and Switzerland and there were many Chileans. There was a relaxed atmosphere with many local families present. We gave solar glasses to the police on crowd control duty. Members of our group were interviewed by Rapa Nui TV and Chilean journalists.

At 12.40 ‘first contact’ (when the edges of the Sun and Moon first meet) occurred behind a cloud but it quickly passed. Everything stopped, people viewed through their special eclipse glasses and cameras started clicking. By 1:40pm we began to use Lisa’s pinhole paper camera and Barbara’s hat gave us a wonderful array of tiny partial eclipse images.

“The light is getting softer, European” said Robin. Then at 2:08pm totality began with a brilliant diamond ring effect. The temperature had dropped, there was a roar from the crowd, traditional drums beat their rhythm, and fire sticks were waved – a unique cultural background for this eclipse. “It’s unbelievable” said Robyn. Totality lasted 4 minutes 39 seconds.

Totality! July 11, 2010, Rapa Nui. Photo Andrew Jacob.

“The diamond ring goes really fast” said Barbara. “Spectacular, the weather cleared perfectly” said Mel. “It was the fastest four minutes in my life” Toner exclaimed. “Everything flew out of my mind” said Ross. “What a blast” said Mike. “It was so much more than I imagined” said Jantina, our guide. “Beyond description” exclaimed Lilly. “I didn’t expect it to get so cold” said Carmel. “I’ll pop the champagne cork’ said Neville. “I was amazed by the shadow coming across the water” said Lesa.

And, after the rain and wind of the last few days Val summed it all up with “We are fortunate”.

From Toner and Andrew.

Henry writes “A layman’s guide to the July 2010 Total Solar Eclipse”

Dr Henry Woodruff is a guide at Sydney Observatory and acting Curator of Astronomy

Image courtesy of Fred Espenak – NASA/Goddard Space Flight Center

On July 12 2010 the Moon will once again throw its shadow on the Earth, in an event astronomers like to call a solar eclipse. And since the Sun will be entirely hidden behind the Moon, we call it a total solar eclipse (as opposed to a partial solar eclipse).

We live in astronomical goldilocks times, since the distance of the Moon from the Earth is juuuust right, so that the apparent size of the Moon is very close to that of the Sun, allowing for spectacular solar eclipses. This will not always hold true, since the Moon is slowly edging away from us at roughly 38 mm every year. Give it enough time and the Moon will appear smaller than the Sun in the sky, and will not be able to completely “cover it up”.

Unfortunately, the path of the Moon’s shadow will not pass any part of Australia this time. Instead, some of the South Pacific and a tiny bit of South America will witness this special event (see eclipse map above , courtesy of Fred Espenak – NASA/Goddard Space Flight Center).

The partial eclipse will begin at 3:09:41 on Monday morning, July 12 2010 (all times are AEST, i.e. Sydney time). The total eclipse begins over an hour later, at 4:15:15. The Sun, Moon and Earth will be “exactly” lined up at 5:34:38, and those lucky enough to view the total eclipse will regain view of the Sun’s edge at 6:51:42 and will be able to breathe freely again at 7:57:16, when the last bit of the Moon fully uncovers the Sun.

The next solar eclipse will not be visible from Sydney until July 22 2028. However, just to put those who believe the world will end in December 2012 on edge, there will be a total eclipse visible from Cairns and surrounds on November 14 2012. Perhaps some money can be made that day :)

Moon to lose big bite on Saturday night – the partial lunar eclipse of 26 June 2010

The Moon during the peak of the partial lunar eclipse at 9:38 pm on 26 June 2010. The main maria or seas on the Moon are indicated. Image Nick Lomb using Stellarium software and with information from Harry Roberts’ Moon map in the 2010 Australian Sky Guide.

When is the eclipse?
There is a partial eclipse of the Moon on the evening of Saturday 26 June 2010. The eclipse is visible from anywhere in Australia and is completely safe to watch. It begins at 8:16 pm AEST and ends at 11:00 pm. At the peak of the eclipse at 9:38 pm just over half the Moon’s width will be eclipsed.

How do eclipses occur?
Eclipses of the Moon occur when the Moon moves into the shadow of the Earth. When the Moon is fully immersed in the dark part of the shadow we see a total eclipse of the Moon. At such times the eclipsed Moon usually takes on a dark reddish colour from the light bent or refracted onto the Moon by the Earth’s atmosphere. When the Moon is only partially immersed in the dark part of the shadow, like tonight, we have a partial eclipse.

How eclipses of both the Sun and Moon occur. Sketch Nick Lomb

An eclipse of the Moon can only happen at full Moon phase. It does not happen every month as the path the Moon takes around the Earth is tilted by about 5° to the path the Earth takes around the Sun. Hence at full Moon the Earth’s shadow usually falls below or above the Moon.

What is the history of Moon eclipses?
Eclipses of the Moon first provided proof that the Earth is a globe as the edge of the Earth’s shadow moving across the Moon is always part of a circle. This was noticed by the Greek philosopher Aristotle who lived in the fourth century before our era.

According to ancient Chinese legend an eclipse of the Moon occurs when a dragon begins eating the Moon. Hence the tradition in China during eclipses was to make as much noise as possible by banging on drums and pots to scare away the dragon. This technique has so far succeeded on each occasion.

Features on the Moon
With the unaided eye you can see dark patches on the Moon – these are the maria, Latin for seas, as they were once thought to contain water. The eclipse provides a good opportunity to identify these features as they are covered and then uncovered by the Earth’s shadow – see the annotated drawing of the Moon above drawn for the peak of the eclipse at 9:38 pm. Mare Tranquillitatis or Sea of Tranquillity was where the American astronauts Neil Armstrong and “Buzz” Aldrin landed on the Moon in July 1969.

Seeing and photographing the eclipse
It is safe and fun to do yourself and you can do so from anywhere in Australia. However, if you are lucky enough to live in Sydney you have the opportunity to do so from Sydney Observatory. The Observatory will be open for viewing of the eclipse through telescopes and there will be the opportunity to take photographs as well.

Partial eclipse of the Moon
Saturday 26 June
8pm – 11pm
A partial eclipse of the Moon, visible across the continent, takes place on the evening of Saturday 26 June. The Moon enters the Earth’s shadow at 8:16pm and leaves the shadow at 11:00pm. The evening includes telescope viewing and short talks about the Moon. Hot drinks and snacks will be available for purchase.
Cost: $15 adult, $12 conc., $10 child, $45 family.
Members: $13 adult, $10 conc., $8 child, $34 family.
To make a booking, telephone 9921 3485