Canis Major star map
Copyright: Melbourne Planetarium
Highlights of the tour:
- two bright star clusters
- binary stars
- the Crab Nebula
The constellation of Taurus can be found next to Orion and represents a mythical giant bull, which is confronting the Hunter, Orion. It is one of the 12 constellations of the traditional Zodiac, in which we find the Sun, Moon and planets throughout the year. From Melbourne, it is best seen during summer, when it is in our northern skies.
Stop 1
This V shaped group of stars represents the Bull’s head, and is actually a cluster of stars called the Hyades. This cluster contains several hundred stars, well over 100 of which will be visible with binoculars. The whole of this cluster will fit in the field of your binoculars, so there will be many stars to see. All of these stars are roughly the same age, having formed from the one gas cloud, but vary in brightness and colour. The brightest star you can see here is called Aldebaran, which marks one of the eyes of the Bull. Aldebaran is not part of this cluster, but is actually in front of it. Aldebaran is 65 light-years away, half the distance to the centre of the Hyades cluster. The brightest star in the cluster is Theta Tauri, a double star system just to the right of Aldebaran. Both stars can be easily seen and through binoculars a colour difference is noticeable, the brighter star being white and the other being orange. Another double star system in the Hyades is Sigma Tauri, just below Aldebaran. Aldebaran itself is a double star, but the smaller of the two is too faint to be seen without a powerful telescope.
Stop 2
You are now looking at another star cluster, the famous Pleiades, or Seven Sisters. This cluster is 410 light-years away and contains hundreds of stars in an area just over 1° across. Due to this grouping being so compact, it appears to be brighter than the Hyades. This is a young cluster, and all the main stars are hot and bluish-white in colour. There is a faint nebulosity about this cluster, though it can be difficult to see. The main stars in the Pleiades, starting with the brightest, are: Alcyone, Atlas, Electra, Maia, Merope, Taygeta, Celaeno and Pleione.
Stop 3
The bright star in this field is Zeta Tauri, marking the end of one of the Bull’s horns. Just below and to the left of this star is the Crab Nebula, or M1. Unlike the other objects in this tour, the Crab Nebula cannot be seen with standard 7 x 50 binoculars, requiring at least a magnification of 12, or a telescope. We include it, however, as it is an interesting and important object. The Crab Nebula is the remains of a supernova seen in 1054 AD and documented by Chinese observers. It appeared as a brilliant star, bright enough to be seen during the day. Today it is a large, irregular and expanding gas cloud. At the centre of this cloud is a pulsar, a rotating star which emits a beam of radiation, somewhat like a beam of light from a lighthouse. We detect this radiation as a regular pulse of energy. The Crab Nebula is the best example of a supernova remnant in the sky.