MV Blog


Total Lunar Eclipse

by Tanya
Publish date
2 April 2015
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A total lunar eclipse will be visible from across all Australia this Saturday, April 4. But it will be a quick one. Rather than passing deep into the Earth’s shadow, the moon is skimming close to the shadow’s edge, as seen in this animation.

Total Lunar Eclipse - December 2011 The moon moves out of totality as seen from Sydney during the December 2011 eclipse.
Image: Neerav Bhatt
Source: Neerav Bhatt/flicr

The period of totality, when the moon is fully enclosed in the Earth’s umbral shadow, will last just five minutes or so. This makes it the shortest total lunar eclipse of the 21st century.

In fact, this eclipse has the shortest period of totality for almost 500 years. Back in 1529, on October 17, there was an eclipse where totality lasted for just 1 minute and 42 seconds.

The moon's passage through the Earth's shadow The moon skims the edge of the Earth’s umbral shadow. Note: this graphic is oriented for the southern hemisphere.
Source: Museum Victoria

How to see it?

The great thing about lunar eclipses is that no special equipment is required to view them. Just look for the moon, which will be visible in the north-eastern sky, weather permitting.

Eclipse timings Local circumstances for the eclipse.
Source: Museum Victoria

From Western Australia, the eclipse begins shortly after sunset with the moon low to the eastern horizon. However, by the time of totality the moon will have risen to a great vantage point.

For the rest of Australia, the eclipse occurs an hour or two after sunset.

The whole event will last for three-and-a-half hours – it’s only the moment of totality that will be very short.

Total Lunar Eclipse - April 2014 The moon disappears into shadow during the total lunar eclipse of April 2014.
Image: Phil Hart
Source: Phil Hart

Watching the moon slowly enter into the Earth’s shadow is always an amazing sight. And it’s during this partial phase of the eclipse that the shadow appears lovely and dark – seen in sharp contrast to the part of the moon which is still in sunlight.

Because totality is very brief and the moon sits so close to the shadow’s edge, this eclipse will not give us a deep red moon. Instead, we will likely see a variation in tone across the face of the moon.

The southern region of the moon – the topmost part as viewed from Australia – travels deeper through the shadow and should take on a reddish-orange glow. Whereas the northern part (or the bottom of the moon) that skims the shadow’s edge, will remain fairly bright.

Total Lunar Eclipse - October 2014 The moment the moon enters totality during the October 2014 lunar eclipse. A similar variation in colour across the moon is expected for this upcoming eclipse.
Image: Martin George
Source: Martin George

Where the shadows lie

What’s interesting to note about this eclipse, is that it’s a great test for eclipse modellers. It’s not surprising, that there is no sharp edge to the Earth’s shadow and therefore the timings of this eclipse are highly dependent on the model used to estimate the shadow’s size.

This was first recorded in the early 18th century when the French astronomer and mathematician Philippe de La Hire realised that to match the timings of a lunar eclipse, it was necessary to increase the predicted radius of the Earth’s shadow by 2.4%.

In fact, observations of lunar eclipses over the next 200 years showed that the size of the Earth’s shadow varied slightly from one eclipse to another.

By the late 19th century a standard value of 2% was adopted as the most effective increase to be made to the Earth’s shadow size to produce the best predictions for an eclipse.

The ‘fuzziness’ of the Earth’s shadow is due to a number of factors such as the sun’s apparent size and the transparency of the Earth’s atmosphere. Eclipse models also have to take into account the fact that the Earth isn’t completely round, but flattened slightly towards the poles. And even the Earth’s axial tilt can add a small variation in the size of the Earth’s shadow depending on what season it is on Earth.

But for most lunar eclipses, these variations have a small effect on the eclipse timings, amounting to differences of the order of 20 seconds or so. But because this eclipse occurs so close to the edge of the Earth’s shadow the model used is much more critical.

Timey wimey

For this article, I’ve sourced the eclipse timings from NASA’s eclipse website maintained by Fred Espanek, a retired astrophysicist from NASA’s Goddard Space Flight Center. His Earth shadow model is the smallest and gives the shortest period of totality at 4 minutes and 38 seconds.

But it’s not surprising that other reputable eclipse models are found to give different results. Australian David Herald is the author of the fantastic Occult program that predicts all types of occultation events (such as the Saturn occultations we saw last year), and it also predicts eclipses. The latest version of his program (Occult4), measures totality for this eclipse as lasting 7 minutes and 14 seconds.

While the longest measurement of totality is sourced from the U. S. Naval Observatory. Their lunar eclipse computer gives a prediction of 12 minutes and 18 seconds.

But what will we see?

What this highlights for me, is the beauty of nature. We can do our best to predict what will happen, but sometimes we just don’t know for certain until we see the event itself. And it’s one of the lovely things about lunar eclipses that each one is unique.

With this eclipse, it is the path through the Earth’s shadow which makes it particularly different. But what can also affect eclipses is how dusty the Earth’s atmosphere is at the time. The dustier the atmosphere the more light is blocked.

That’s when the moon can turn a really deep red, like it did 2011 when the atmosphere was full of ash from the eruption of Chile’s Puyehue-Cordon Cualle volcano.

Even nonlocal weather conditions can affect the appearance of a lunar eclipse. Storm systems and poor weather in the part of the world where the sun ‘disappears’ as seen from the moon, will make the atmosphere less transparent. In particular, if it’s a very deep eclipse and the moon passes right through the centre of the Earth’s shadow, such weather systems can help to deepen the Earth’s shadow so that the eclipsed moon becomes almost impossible to see.

So why not try your hand at timing this eclipse event and see which model gives the best prediction for you?

And while you are watching the eclipse, the star to the right of the moon is called Spica, the brightest star in the constellation of Virgo. While in the east Saturn will be visible at the head of Scorpius and over in the north-west Jupiter can be found shining brightly.

But if the weather doesn’t cooperate in your local area, you can also follow the eclipse via live streaming by Sydney Observatory, Slooh or the Virtual Telescope.

Most importantly, this lunar eclipse is well worth a look because it will be a while before we get the chance to see another. The next lunar eclipse to be seen from Australia is a partial one on August 7, 2017 and only 25% of the Moon’s diameter will be in shadow. The next total lunar eclipse won’t occur until January 31, 2018.

Many thanks to Martin George, Curator of Astronomy and Assistant Director, Queen Victoria Museum, Launceston, for very useful discussions that improved this article.

The Conversation

This article was originally published on The Conversation. Read the original article.


Watching the total solar eclipse

by Tanya
Publish date
14 November 2012
Comments (0)

I had never seen a total solar eclipse before, and I was very excited to travel to Queensland to watch Australia's first solar eclipse in a decade just before 6AM this morning. 

It was incredible to wander down to the beach at 4AM and see it already packed with eclipse chasers! Thousands of people were at Palm Cove alone, more in surrounding Cairns and Port Douglas, while some headed inland where the weather prospects were better.

People on beach Eclipse chasers on the beach at Palm Cove, Queensland, awaiting the total solar eclipse.
Image: Tanya Hill
Source: Tanya Hill

We saw a magnificent sunrise over the water, but minutes later, when the partial eclipse was due to begin, the Sun disappeared behind clouds. It was an anxious wait but half an hour later, the clouds parted and we all donned our eclipse glasses to see a large chunk missing from the Sun.

The totality was perfect. Just beforehand you could tell that the surrounding light was different; it seemed sharp and unnatural. Then the brilliant diamond ring effect lit up the bottom of the sun and the moment had begun.

Total solar eclipse The moment of perfect totality, when the Moon was exactly in front of the Sun.
Image: Tanya Hill
Source: Tanya Hill

I was amazed by the colour - we could really see the pink prominences dancing around the Sun. Everyone cheered and just enjoyed the beauty of this natural show. We could see Venus shining bright above the Sun, the wispy corona and the Sun's outer gaseous layer, along with a dazzling bright ring encircling the Moon. It was surprising how long the two minutes lasted. The second diamond ring effect was blinding and spectacular as the Sun began to emerge once again.

The Yolngu of Arnhem Land tell their eclipse story of the sun-woman and moon-man coming together in the sky as husband and wife. It struck me that this is a phenomena that has been seen by so many, across thousands of years. I feel so fortunate to have shared in the experience.


'Eclipse groupies take shot in the dark,' The Age, 11 November 2012

'Eclipse sheds light on sizzling sun,' The Age, 14 November 2012 

Tribute to Neil Armstrong

by Tanya
Publish date
27 August 2012
Comments (2)

I was sad to hear the news yesterday that Neil Armstrong had passed away.

Neil Armstrong Neil Armstrong in Apollo Lunar Module after his historic moonwalk in July 1969.
Source: NASA

It was just last week that I had been talking about the Apollo missions to a group of Grade 3 students. It was my son's class and they had asked me to talk about life on Mars. They were studying the idea that over time, living things need to adapt in order to survive, and so they were thinking about what people would need to live on Mars one day.

As we spoke about things like the need for water and oxygen, along with the differences between Mars and Earth, I asked if they'd ever seen what happened when the astronauts walked on the Moon. The group, including my son, looked at me blankly and I realised that they had never heard of the famous Moon landings.

So we checked out the NASA clips of Apollo 11's landing and those great action shots of astronauts bouncing around on the Moon due to its weak gravity. The kids were astounded!

spacecraft on Moon Photo of Apollo Lunar Module on the surface of the Moon with Armstrong's shadow in the foreground
Image: Neil Armstrong
Source: NASA

I was born just as the Apollo missions were coming to an end. Even so, it was always a part of my world. The Apollo astronauts were amazing men and my tribute to Neil Armstrong will be to make sure that young generations know of the incredible things he and his fellow astronauts did. May they always be an inspiration to all.


Statement from Armstrong Family (via

Moon gazing across the globe

by Nicole K
Publish date
22 July 2012
Comments (6)

Your Question: How can my wife and I gaze at the full moon together, but from opposite sides of the globe?

Our enquirer is in Jervis Bay, on the East Coast of Australia. His wife is in Ottawa, Canada. They contacted Museum Victoria to ask if we can help them plan a romantic evening – a full Moon-gazing date on opposite sides of the Earth.

A full moon seen from Ontario, Canada. A full moon seen from Ontario, Canada.
Image: Michael Gil
Source: Wikimedia Commons

The next full Moon will occur on the 1st or 2nd of August 2012 (depending on what time zone you are in). In Ottawa, the Moon will rise at 7:55pm EDT (Eastern Daylight Time) on 1 August. It will be at its absolute fullest at 11:27pm and will continue to be visible until it sets on 2 August at 6:28am.

Sadly in Jervis Bay's time zone, the full Moon will occur when the Moon is not visible from that side of the Earth, at 1:27pm AEST (Australian Eastern Standard Time). The Moon will have set that morning at 6:24 and will not rise again until 5:32 that evening.

All is not lost, however. The Moon-watching date can still occur, just not at the precise moment when the Moon is at its fullest. Our couple will just have to wait a few hours.

When the Moon rises on the night of 2 August in Jervis Bay (at 5:32pm AEST), it will be 3:32am in Ottawa (EDT). The Moon will be visible in both places and will remain so until it sets in Ottawa at 6:28am (EDT). This means our two Moon-gazers can watch the still-very-full Moon "together" for nearly 3 hours.

If the idea of getting up so early diminishes the romance from the Canadian perspective, our Moon-gazers can wait a few days – if they are happy to look at a Moon that is no longer full.

On 4 August, the Moon will rise in Jervis Bay at 7:38pm (AEST). It will be 6:02am in Ottawa (EDT). The Moon will be visible in both locations until it sets in Ottawa at 8:48am. Unfortunately this means the Canadian half of our Moon-gazing couple will be looking at the Moon during daylight (the Sun will rise in Ottawa on 4 August at 5:51am).

While arranging this date was tricky, it was only possible because our lovers are not on exactly opposite sides of the Earth. If they were, there would be no chance of viewing the Moon that the same time (for more than an instant and only then if they had a perfect view of the horizon). And one of them would have to be in a boat. Less than 4% of all land on Earth (and no part of the Australian mainland) is antipodal (diametrically opposite) to land: the antipode of Jervis Bay is in the North Atlantic Ocean; the antipode of Ottawa is in the Indian Ocean.

Maps showing Jervis Bay, Australia, and its antipode, in the North Atlantic Ocean. Maps showing Jervis Bay, Australia, and its antipode, in the North Atlantic Ocean.
Image: Antipodes Map
Source: Antipodes Map


Melbourne Planetarium: Skynotes

Melbourne Planetarium: Moon Phases

US Navy: Rise/Set times for Sun/Moon

Antipodes Map

Moon rock now on display

by Ursula
Publish date
19 June 2012
Comments (6)

Ursula Smith works in the natural sciences collections at Museum Victoria. Though a palaeontologist by training she finds all the collections fascinating and swings between excitement at all the cool stuff in them and despair at the lack of time to look at it all.

Museums make it possible to see specimens from faraway places that you won't get the chance to visit yourself. And it doesn't get much further away than the Moon – a piece of which we've received on long-term loan from NASA for display in Dynamic Earth. It was installed just this morning.

Moon rock Moon rock in its protective glass case, now on display in Dynamic Earth. Behind it is the exhibition's Moon model.
Source: Museum Victoria

It's a small piece cut from a larger rock, lunar rock 15555, dubbed 'The Great Scott' after Commander David Scott who collected it during the Apollo 15 Lunar Mission in July 1971. Its specially-built glass case is filled with nitrogen to protect the rock from Earth's atmosphere.

Moon rock is incredibly rare - we have not quite 800kg in total on Earth, which is lighter than an average family car. It's also incredibly important because of what it can tell us about the Moon's formation.

The Great Scott is a basalt formed from a volcanic eruption. It's similar to basalts found on Earth, being composed of silicate minerals such as olivine, pyroxene and plagioclase, except that basalts from the Moon lack water.

Great Scott moon rock Apollo 15555, 'The Great Scott'. The dent in the centre of the visible surface is a "zap pit" - a hole caused by the impact of a micro-meteorite.
Source: NASA

The Great Scott is 3.3 billion years old and has been sitting on the surface of the Moon for 80 million years, since long before the dinosaurs went extinct! We can tell this by measuring how long its minerals have been exposed to cosmic radiation. The rock still looks amazingly fresh because the Moon has no atmosphere, meaning very little weathering has occurred.

Apollo 15 was the fourth of the Apollo missions to land on the Moon and the first to involve significant geological training for the crew. 

Three men in space suits The Apollo 15 Crew standing in front of the Lunar Rover: Cmd. David Scott, CMP Wolden, LMP Irwin.
Source: NASA

The landing site for Apollo 15, Mare Imbrium, was selected specifically to allow investigation of three different landscape features: a mare basin, a mountain front and a lunar rille. Mare Imbrium is so large that it's visible to the naked eye from Earth. It was hoped that Apollo 15 would be able to collect Pre-Imbrian material – rock exposed or thrown out by the impact that formed the enormous crater.

  The Moon showing Mare Imbrium. The Moon showing Mare Imbrium.
Source: Wikipedia

Another of the primary goals of the Apollo 15 mission was an examination of Hadley Rille, a channel-like depression in the lunar surface. During their three-day stay on the Moon, Scott and Irwin traversed over 28km in the lunar rover – the first time a vehicle had been driven on the Moon's surface.

At Hadley Rille they collected a large proportion of the rocks that were brought back to Earth, including Apollo 15555. Weighing 9.6kg on Earth, the rock weighed only 1.6kg on the Moon so it was easy to carry.

Moon rock in situ on the Moon Apollo 15555 prior to Commander Scott collecting it. The tripod structure is a gnomon used to indicate the direction and elevation of the sun.
Source: NASA (Image AS15-82-11164)

NASA distributed rock from the Apollo missions to researchers around the world for study, including Museum Victoria Honorary Associate Professor John Lovering. At the time of the Apollo program he was the Head of Earth Sciences at the University of Melbourne.

Professor Lovering carried out some of the very first chemical analyses of the Moon rock from Apollo 11 and 12, and discovered a new mineral, tranquillityite, which has since been found on Earth – from six localities in Pilbara, Western Australia – as well as from rocks from every Apollo mission and a lunar meteorite.

Man and vehicle on the Moon LMP Irwin and the Lunar Rover, taken by Cmd. Scott
Source: NASA (Image A515-86-11603)


Infosheet: The Moon

MV Blog: Distant Moon

Apollo Lunar Surface Journal

Lovering, J. F. et al (1971). Tranquillityite: A new silicate mineral from Apollo 11 and Apollo 12 basaltic rocks. Proceedings of the Lunar Science Conference 2: 39–45.

MV Blog: Murchison meteorite

Partial lunar eclipse

by Tanya
Publish date
2 June 2012
Comments (1)

Tonight the Moon, Earth and Sun will fall into line to create a partial lunar eclipse. Between the hours of 8pm and 10pm, a small section near the top of the Moon will plunge into the Earth's shadow.

This event has been somewhat overshadowed (ha! ha!) by the Transit of Venus that occurs on Wednesday. But I must say, that I have a particular love of lunar eclipses. I think it's because they happen at night - so not only do you get to see the eclipse, but you can also check out the starry night sky.

9pm, 4 June 2012 The eclipsed Moon will be found below the constellation of Scorpius, at 9pm on 4 June (created using the Starry Night software).
Source: Museum Victoria

This eclipse will occur in the eastern sky, with the Moon just beneath the constellation of Scorpius - one of the constellations that really is true to its name. Looking at the curving line of stars, it is easy to picture a Scorpion up there in the sky. And if you are away from city lights, then you'll see the brightest part of the Milky Way, which lies towards the Scorpion's tail.

The other great thing about lunar eclipses is that you don't need any special equipment at all to view them. Just a clear night sky and the willingness to spend some time outdoors, marveling that we are part of a much larger Universe.

Lunar Eclipse Sequence Progression from a partial to total lunar eclipse, Pennsylvania, December 2010.
Image: Anthony Skorochod
Source: Wiki Commons

About this blog

Updates on what's happening at Melbourne Museum, the Immigration Museum, Scienceworks, the Royal Exhibition Building, and beyond.