COTM: Coma Berenices

Mike Nelmes

The hair of Egypt's Queen Berenice found its way into the celestial sphere under unusual circumstances. The story goes that she cut it off and presented it to the gods, in gratitude for the safe return of her husband from battle. In 1602, Tycho decided to place it between Virgo, Leo, Canes Venatici and Bootes. This month we find this faint, medium-sized constellation fairly high in the north in the early evening. Observers in North Canberra will have an advantage.

Home to some of the thousands of galaxies that make up the great Coma-Virgo cluster (not to be confused with the Coma star cluster to which its naked-eye stars belong), Coma Berenices is primarily a hunting ground for faint fuzzies. As with neighbouring Virgo, a careful sweep through it will be rewarded by sightings of multiple galaxies within one field of view. Perhaps we should set a challenge: Who can count the most in one field? Of course, a combination of large aperture, wide field of view and dark sky will be an advantage.

My observations were made from Spence with tripod-mounted Celestron 25x100 binoculars. Pleasant viewing for this selection.

M64 (NGC 4826) - The Black Eye Galaxy. Found along a line joining stars alpha and gamma. Binoculars show it elongated roughly east-west, the 5th magnitude binary star 35 Com sitting well within the field. Larger apertures show a distinctly dark dust region near the centre of this spiral, hence the name.

NGC 4565 - The Needle Galaxy. Continuing along the line from M64 towards gamma we find this thin, edge-on spiral about 12 arcminutes long, described by Hartung as 'remarkable'.

M85 (NGC 82) and M100 (NGC 4321) at magnitude 9 form the brightest two of a rich galaxy concentration along the southern Virgo border. The former has a brightish star adjacent. Other 9-10 magnitude Messier galaxies in the region include M88, M91, M98 (NGC 4192, edge-on spiral) and M99 (NGC 4254, face-on spiral). Over the border in Virgo, another eight or so can be found, including the intriguing giant elliptical M87.

OK, enough with the galaxies. A few star clusters and doubles:

Melotte 111 - a loose, naked-eye scattering of about 30 stars spread over six degrees or so. Best seen in low-powered binoculars such as 7x50s. Look for a faint asterism along the north-east edge: an unusually straight line of four stars.

M53 (NGC 5024) - With a bright diffuse core, this compact (class 5) globular cluster of magnitude 7.7 sits adjacent to a pair of stars which give the impression of eyes above it. Hartung called it ‘very fine’.

NGC 4147 - Small, moderately bright globular cluster, 1.5 arcminutes in size, west of M85.

2 Com - double star of magnitudes 6 and 7.5, separation 4 arcseconds.

Struve 1633 - double star of magnitudes 7 each, separation 9 arcseconds.