Coma Berenices
The girl, she got long black wavy hair
Coma Berenices is a spring constellation which points the way to galaxies and the wonders of deep space. It follows last months Constellation of the Month, Leo, in the sky and in fact Coma was once not a constellation in its own right, but a part of Leo - his tail.
Coma Berenices (Koh-ma Be-ren-i-sez), hereafter shortened to Coma, is a fairly modern constellation, only appearing on star maps in the late 16th century. Despite this its mythology has been well documentated. The astronomers of Ancient Greece referred to it often as either the locks of Ariadne or those of Berenices (depending on who had made the cover of Hello! that week). Berenice was a Queen of Egypt and wife to King Ptolemy III, who erected the first of the three Rosetta Stones (the third one being the one known throughout the world).
Ptolemy waged war against the vicious Syrians and Berenice, fearing for her husbands life promised to the Goddess Aphrodite that if he returned safely she would cut off her beautiful flowing dark locks. He did return safely and Berenices duly made her sacrifice, placing the hair on the temple altar.
The next morning came and the palace was in uproar; the hair had disappeared and it looked like the temple priests were about to take a step closer to the other side. Thankfully (and aren't they always the heros in such stories) the court astronomer stepped in, proclaiming that the hair had been gratefully taken by Aphrodite and raised into the heavens for all to see.
Stellar Sights
Coma is not a particularly bright constellation, its dim stars quickly succombing to light pollution, but on a transparent, moonless night look to the left of the hind quarters of Leo and you might be able to catch the twinkle of the Coma Star Cluster (Mel 111). On the map above this is located just to the right of gamma and is a beautifully disperse open cluster just on the edge of naked eye vision.
Coma only has one named star, alpha which is called Diadem, the diamond in Berenice's crown and two other stars with bayer designations, beta and gamma. All three are fourth magnitude and represent the brightest stars in this dark area of the sky. Amongst the other stars in Coma, there are over 200 known variables and some very nice double stars. My personal favourite is 24 Comae, also known as the Spring Albireo, as it has beautifully constrasting golden and blue components, albeit dimmer (5.2 and 6.5 magnitudes respectively) than its namesake in Cygnus.
Coma also contains the north galactic pole located at right ascension 12h 51.42m and declination 27° 07.8' (epoch J2000.0)
Into the Deep
Coma lies at one end of the famous Coma-Virgo supercluster of galaxies, and as with Leo, is therefore a prime hunting ground for these distant objects in space. Coma contains 7 Messier galaxies, 6 of which are members of the Virgo cluster, around 60 million ly away.
M64 is known as the Black Eye Galaxy because of its prominent dark dust lane in front of the galaxy's bright nucleus. It lies around 17 million light years away from Earth and is therefore not a cluster member. It is believed that a satellite galaxy collided with M64 in the last billion years or so as observations show that the outer galactic material rotates contrarywise to the inner material closer to the galactic core.
M100 and M99 are two other highlights in this area. Both of them are face-on spirals with M99 displaying slightly more detail to the small scope - perhaps even a hint of spiral arms in a 4-6".
The other Messier galaxies in this area are M85, M98, M88 and M91. M88 is orientated in a similar way to the Andromeda Galaxy, M31, whilst M98 is an edge on galaxy, offering greater brightness and increased visibility.
Our final galactic target is NGC 4565, an edge-on spiral galaxy known as the "Needle Galaxy". It is one of the largest edge-on spirals to be seen from Earth and has a dark dust lane that can be seen with a 6" telescope on a good, clear dark night.
Coma also contains a few Globular Clusters, the brightest of which is Coma's eighth and final Messier object, M53. It was discovered by Charles Messier in February 1777 and is of magnitude 7.7, making it visible in binoculars. It is around 65 kly away and its total luminosity is around 200,000 times that of the Sun.
Conclusion
The Coma area has much to offer for someone wishing to wade into slightly more difficult waters. The objects discussed here are somewhat dimmer than we might usually look at, but with a little determination and the right skies, they will prove to be just as rewarding as anything seen previously.
Clear Skies
Nick Bramhall
May 2006