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DISPLAYING POSTS TAGGED: eclipse (4)

Solar eclipse from space

Author
by Tanya
Publish date
31 January 2014
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During the early hours of this morning, from 12:30am to 3am, NASA's Solar Dynamics Observatory captured a stunning solar eclipse from space.  The Observatory sees a number of eclipses each year, but this was the longest one that's been recorded so far.

 

The eclipse was visible from the Observatory's vantage point, orbiting 36,000km above Earth. Since it could only be seen from space, the event is technically called a lunar transit. At its peak, the Moon covered up to 90% of the Sun.

Just as the Moon moves away, you can see a solar flare erupting from the left hand side of the Sun. This is just the kind of activity that the Observatory is helping scientists to better understand.

Solar Flare from the Solar Dynamics Observatory Perfect timing as the Sun releases a solar flare.
Source: NASA
 

Launched into space on 11 February 2010, the Observatory is on a 5 year mission to study the Sun as part of NASA's Living with a Star program. Our Sun is very active releasing flares and eruptions that can send energetic particles hurtling towards Earth. This can play havoc with our technological systems, bringing down power grids and causing blackouts. The ultimate aim is to better understand the cause of the Sun's activity so that one day we may be able to predict when such flares will occur to give us some prior warning.

The Observatory takes an image of the Sun every 0.75 seconds, and you can see all the beautiful images at the Observatory's Gallery. We have been loving the Gallery here at the Planetarium, and some of the footage will be featured in a new planetarium show to be released later this year.

Annular Solar Eclipse

Author
by Tanya
Publish date
8 May 2013
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On the morning of May 10, the Moon will meet up with the Sun in the sky. Many places across Australia will experience a partial solar eclipse - here in Melbourne, 37% of the Sun’s diameter will be blocked by the Moon. It’s not enough for us to notice any visible effects, but if you use the right observing methods (as described below), it’s a neat thing to watch.

However, along a narrow line across the top of Australia, including Tennant Creek (NT), an annular eclipse will occur. What happens here, is that the Moon directly lines up with the Sun, but the Moon is too small to block the Sun completely. Instead, we are left with a ring of sunlight shining out from around the dark Moon.

Annular Solar Eclipse from the Hinode satellite The satellite Hinode, a Japanese mission in partnership with NASA, NAOJ, STFC, ESA and NSC, observed this annular eclipse on 4 January 2011.
Source: Hinode/XRT
 

Skynotes readers will be aware that the Moon’s distance to Earth varies throughout the month. At perigee, when the Moon is closest to Earth, it’s around 360,000 km away. But at apogee, when the Moon is furthest from Earth, its distance increases to about 400,000 km. Well this month, apogee occurs on May 13, a few days after the eclipse. Being further away, the Moon appears smaller and no longer matches the size of the Sun.

It’s such a great coincidence that we have solar eclipses at all. Who ever thinks much about the Sun and Moon appearing the same size, even though they are at such different distances from Earth? Having seen my first total solar eclipse last November, I’m really glad this coincidence occurs, as it was an amazing sight.

Timings of the partial eclipse from Melbourne on Friday 10th are:

Eclipse begins: 7:50am
Mid-eclipse: 8:52am
Eclipse ends: 10:02am

Remember, it is not safe to look directly at the Sun. There are safe ways to look at the eclipse – at the Scienceworks shop you can purchase special eclipse glasses that will allow you to watch the event, while protecting your eyesight.

You can also create a simple "pinhole" projection. It's as easy as making a small pinhole in a piece of paper or cardboard. Do not look through the hole, but allow the Sun to shine through and project an image onto a second piece of cardboard. Even a blank wall or clear patch of ground can make good surfaces for projection.

Sometimes nature helps out too. If you can see sunlight travelling through the leaves of a tree, you’ve got yourself some ready made pinhole projections. Check the ground and it might be covered with little eclipse images. Take a look at this great example on the Astronomy magazine website.

Links:

Australian Astronomy Factsheet : for eclipse timings from other Australian cities.

Total Lunar Eclipse

Author
by Tanya
Publish date
8 December 2011
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Comments (3)

I don’t know about you, but I’m already feeling the pressure of December madness. Really it’s a fantastic time of the year when we catch up with friends, celebrate with colleagues and generally wind things up for the summer. But cramming all this in alongside final deadlines and the Christmas shopping can be a mighty task!

When it all gets a bit too frantic and crazy, there’s nothing like sitting back and taking in the night sky. And this month, there’s even more reason to do so.

This beautiful composition shows the extent of Earth's shadow. It was taken from Europe, so might recognise that the Moon appears upside down.This beautiful composition shows the extent of the Earth's shadow. It was taken from Europe, so you might notice that the Moon appears upside down.
Source: Laurent Laveder

During the early hours of Sunday 11th December there will be a Total Lunar Eclipse. We can watch the Moon change colour as it plunges into the Earth’s shadow.  

The eclipse begins at 11:46pm (AEDT) on Saturday 10th December as the Sun, Earth and Moon fall into line. At first, the shadow will appear to take a bite out of the Moon. Then, the Moon will enter full shadow or totality, just after 1am on Sunday morning. It will stay in shadow for 51 minutes, a little on the short side for a lunar eclipse as they often continue for over an hour.

By 2am, the Moon will begin to light up again and it’s amazing how bright that first glimpse can be. At 3.17am all will be back to normal.

The interesting thing about an eclipse is that the shadow isn’t completely dark. The Moon takes on a reddish glow as light travels through the Earth’s atmosphere. Depending on conditions, it can also take on a hint of blue around the edges from light that passes through the ozone layer in the Earth’s upper atmosphere.

So what might we see during this eclipse? On NASA’s Science news website, atmospheric scientist Richard Keen of the University of Colarado says:

"I expect this eclipse to be bright orange, or even copper-coloured, with a possible hint of turquoise at the edge."

Sounds lovely, doesn't it? Apparently our atmosphere is nice and clear at the moment. Let's just hope the clouds stay away.

Best to try for this eclipse as we are coming up to some lean years. The next lunar eclipse will be a partial in June 2012. But to see a Total Lunar Eclipse, we'll have to wait until April 2014.

The Moon plunges into the Earth's shadow.The Moon plunges into the Earth's shadow.
Source: Public Domain

Eclipses are uncommon because the Moon's orbit (shown in green) is misaligned with the Earth's orbit around the Sun (shown in blue). If the Moon and Earth orbited in the same plane, we'd see an eclipse every Full Moon (as well as a solar eclipse every New Moon). But because the Moon's orbit is tilted by just 5 degrees, most of the time the Moon misses the Earth's shadow and moves either above or below it.

So enjoy taking some time out to appreciate the Universe we live in, as long as the weather lets us!

 

A treat for early risers

Author
by Tanya
Publish date
16 June 2011
Comments
Comments (1)

A rare event happened this morning... when my one-year-old started calling out for Mummy just after 4am, the usual dread of having to face another cold and early start was gone, replaced by the thrill that my little guy was just the perfect astronomer!

This morning we were treated to a total lunar eclipse and it began with a beautiful starry, but certainly cold, morning sky. Just before 4.30am a small chunk was seen to be missing from the top right of the Moon. The first sign that the Earth's shadow had found its target.

Lunar Eclipse The Earth's shadow hit its target.
Image: Tanya Hill
Source: Museum Victoria
 

Lunar eclipses occur on those rare occasions when the Sun, Earth and Moon are in perfect alignment. They only ever happen at the time of Full Moon, when the Sun and Moon are on opposite sides of the Earth. Most of the time the Earth's shadow misses the Moon, falling either above or below it, but this morning it was right on track.

By 5am, the Earth's shadow was covering more than half the Moon and a reddish glow was already beginning to appear. The stars was twinkling perfectly, with one of my favourite constellations, that of Scorpius, sitting directly to the left of the Moon, and the centre of the Milky Way right above it. Totality officially began at 5.23am and the Moon was certainly an eerie red colour.

Where does that red come from? Well the only way sunlight can now reach the Moon is by passing through the Earth's atmosphere. That light gets bent and scattered, so only the reddest light can make it through. Particles in our atmosphere, like the volcanic ash that's been annoying so many air travellers these last few days, added to the scattering effect, making the eclipse redder and darker than the last few that I remember.

For those who love statistics, totality was due to last 100 minutes, making it the longest lunar eclipse since 2000, which clocked in at 106 minutes. A rough rule of thumb is that totality generally takes around one hour, but a couple of times each decade we get a good one lasting 90 minutes or more. This was one of those.

Except for those pesky clouds that rolled in just after 6am, blocking the view for those who got up at their usual time. They were obviously in need of my own precious little alarm clock.

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

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