Here’s a constellation that is difficult to locate under light polluted skies and under dark skies has the tendency to get lost among the countless stars that become visible. Look between the constellation Leo to the west and Boötes to the east and there you’ll find the faint constellation of Coma Berenices. The three stars that make up this constellation all fall within forth magnitude range. α Comae Berenices shines at magnitude 4.3 as does γ Comae Berenices. But β Comae Berenices is the brightest star in the constellation shinning at magnitude 4.2. The three stars form a right-angle (sort of).
Coma Berenices is associated with Queen Berenices II of Egypt who was married to Ptolemy III Euergetes around 246 – 221 B.C. According to some mythology, Ptolemy III went on a mission against the Seleucids who killed his sister. The queen, being concerned for her husband’s safety, made an agreement with the goddess Aphrodite where she would cut off her long beautiful hair upon the return of Ptolemy III. Aphrodite, being the goddess that she is, returns Ptolemy III back to the queen and, the queen in turn holds up her end of the deal by cutting off her long beautiful hair and places it in the goddess’s temple. So, the next day, the hair disappears, and of course the king loses his sense of composure over this and threatens to start cutting off heads unless somebody comes forward and confesses to the crime. Well, in walks the court astronomer, Conon, and tells Ptolemy III that Aphrodite was so pleased with the queen’s offering that she placed it in the sky. Conon leads the king outside and points to the stars that have ever since been known as, Berenices Hair.
While Coma Berenices may not be a big or bright constellation, it is home to the North Galactic Pole as well as home to eight Messier objects. We’ll take a look at a couple of the brighter objects and an interesting double star.
Diadem (alpha Comae Berenices/ Σ1728)
The name Diadem is derived from the Greek diádêma meaning “band” or “fillet” and is a binary star about 63 light-years distant and separated by 0.7” (arc-seconds). The two stars are almost identical F5 dwarfs. From our vantage point, both stars appear to orbit each other almost exactly edge-on, causing the stars to appear to move back and forth in a straight line over a 25.8 year period. The pair is an easy split in the 90mm refractor at 75x. Both stars appear white at nearly equal magnitude.
Just about 1° northeast of Diadem is the globular cluster M53. Discovered on 3 February 1775 by Johann Elert Bode who described the cluster as “rather vivid and round”, it was independently rediscovered by Charles Messier two years later on 23 February 1777 and added it to his catalog describing it as “round and conspicuous”. Our observation log dated 4 April 2010 notes that we were operating the 90mm refractor at 48x and reads, “M53 is an easy target. The object appears as a fuzzy disk with a bright and very concentrated center and gently fading toward the edges”.
This is the well known “Black Eye Galaxy” which features a conspicuous dark structure that obscures the stars behind it. Discovered on 23 March 1779 by Edward Pigott (which was largely ignored until the record was recovered by Bryn Jones in April 2002) just twelve days before Johann Bode found it. It wasn’t until almost a year later when Charles Messier independently rediscovered it and cataloged it as M64. Locating M64 can be a little challenging for those of you without push-to or go-to mounts. There are several methods to star-hopping to M64 and one is to locate the 5th magnitude star 35 Comae Berenices and M65 is just about ¾ of a degree east-northeast. Under a light polluted sky a 5th magnitude star may not be visible so our method is to start at Diadem (alpha Comae Berenices) and in a 6×30 finder scope (7° FOV) you’ll also notice the 4.7 magnitude star 36 Comae Berenices. Move your telescope west to center 36 Com. Next, move your telescope north and watch for the 5th magnitude star 35 Com to enter the FOV and center it. Now, switch to your main telescope and with a low power eyepiece center the star 35 Com. Now move your telescope north and watch for M64 to enter along the edge of the FOV and you can center it from there. We have a short video that may help to guide you along. Our observation log of 5 May 2010 indicates we were using the 150mm refractor at 54x, “M64 exhibits a bright core and the dark lane is clearly visible with direct vision.”
This object takes us back to the beginning of this post where Conon, the court astronomer saves everyone from losing their heads. Mel 111 was first cataloged by Ptolemy and although conspicuous it was not included in the NGC catalog or by Charles Messier. Its true nature as a cluster wasn’t proven until 1938 by R. J. Trumpler but prior to this it was cataloged by P. J. Melotte in 1915 as number 111. Mel 111 is easy to locate as a hazy object that appears to be hanging down from the 4.3 magnitude star γ Comae Berenices. The cluster is best viewed with a rich field telescope using low power. We found the best view with our 10×50 binoculars.
While there are a few additional Messier and NGC objects visible in small telescopes in Coma Berenices, I won’t take the time to go through here but, when you do get out to observe, take the time to look at M85, M100 and NGC 4565. Remember that these will be faint and may require a little practice and patience to track down and see. Don’t forget about the averted vision/moving eye technique to help you see faint objects and detail. Remember too, to shield your outdoor lighting down so we can all enjoy the night sky.