This week, we will track down an often overlooked naked eye star cluster; the Coma star cluster, which can be found in the constellation of Coma Berenices, Queen Berenice’s hair. It is not as well known as the Pleiades in Taurus, the bull, but nevertheless gives a distinct sense of satisfaction when identified. While the Pleiades are almost immediately recognisable, it takes a little more effort to track down Coma. The chart shows the view looking south from London on 14 April 2025 at 10pm BST, although the view will remain essentially the same all week. Unlike the Pleiades, Coma is fainter and so a dark sky well away from streetlights will be needed to see the cluster. Whereas the Pleiades contains about six to seven easily visible stars (hence its colloquial name the seven sisters) Coma consists of 10-11 stars. These are fainter to see and spread out over a larger area. Pleiades sits in an area of about four times the diameter of the moon, whereas the Coma cluster is spread over roughly 10 full moons. The cluster is also visible from the southern hemisphere. For example, from Sydney, Australia, Coma Berenices can be seen in the north-northeast in the early to mid evening, crossing the northern meridian at about midnight.
Author: Stuart Clark