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.
The satellite Hinode, a Japanese mission in partnership with NASA, NAOJ, STFC, ESA and NSC, observed this annular eclipse on 4 January 2011.
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:
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.
Australian Astronomy Factsheet : for eclipse timings from other Australian cities.