What's Up in Space
This Weekend’s Night Sky (20 -21 December 2014)
With a new moon on Monday, we may be treated to some wonderful dark skies this weekend, so it’s a good time to look out for some fainter and more diffuse objects.One of the best targets for this time of year is M42, or the Great Nebula in Orion.
Orion is easy to find by the three bright stars that form his belt, which can be seen towards the north east after dark. Here in Aotearoa we call these Tautoru, meaning line of three. Above Orion’s belt is a line of faint stars which form Orion’s sword in the northern hemisphere. For those of us in the southern hemisphere we see the belt and sword instead as a pot or saucepan. If you look carefully you may see the middle star of Orion’s sword has a fuzzy appearance. This is the great nebula in Orion.
The Orion Nebula is a stellar nursery, a huge cloud of gas and dust in which new stars are being born. At around 1,344 light years away, M42 is the closest massive star formation region to the Earth, with around 700 stars in various stages of the star formation process. In the heart of the Orion nebula is a small group of bright stars known as the Trapezium Cluster. The ultraviolet radiation from these stars is lighting up the surrounding gas.
Whilst easily spotted with the naked eye, through binoculars or a small telescope the nebula is a wonderful sight. Take your time and you should be able to clearly see some of the nebulosity of M42 and the bright star cluster that lights it up.
Another nebula in Orion that is well worth a look is the reflection nebula M78, easily found in a small telescope. With a larger telescope the famous Horsehead nebula, or IC434, is a lovely sight just to the south of the star Alnitak in Orion’s belt.
If you would like to try your hand at observing an even more distant object, and you have a clear view of the northern horizon, the Andromeda Galaxy is also still visible low in the north in our evening skies. At 2.5 million light years away, the Andromeda Galaxy is the nearest large spiral galaxy to our own, and the most distant object easily visible to the naked eye. With binoculars or a small telescope, much more detail can be seen.
Image: Andromeda Galaxy – M31, Gustavo Naharro, https://www.flickr.com/photos/gnaharro/9508470901/