Binocular Objects (4): Melotte 111 and M3

On April 11th 2004 I observed Melotte 111(Coma Star Cluster) and M 3 with the Skywindow and my 7x 50 Bresser and the Vixen 15 x 80 binoculars. The seeing was 7 or 8 (on a scale of 10, where 1 = best and 10 is worse).

The Coma Star Cluster was not visible with the naked eye. After searching for a few moments, I found the star cluster in the area between Leo and Bootes with the 15 x 80 Vixen binoculars. I immediately noticed that the Coma Star Cluster is way too big for the 15 x 80 with its 3.5-degree field of view. I switched to the 7x50. The cluster just fitted into the 6-degree field of view of the Bresser. This cluster is really impressive. The sketch below should give you an idea what to expect when observing from a light polluted backyard.

The sketch was made using the 7x50. I also added some fainter stars using the 15x80, but not all stars have been included. I counted between the 50 and 60 stars easily. The faintest stars are of the 10th magnitude. At the heart of the cluster you see a clear triangle of stars, with one bright star right in the middle of the triangle. To the east of the centre, the double star 17 Comae Berenices can be seen. For more background information on the Coma Star Cluster and a finder chart, please read the article "The Coma Berenice Star Cluster" in my "Focus On" section on this site.

Later that night I turned the 15 x 80 to M 3 in Canes Venatici, a globular cluster that lies 1/3 of the way between Arcturus and Cor Caroli . I immediately spotted M 3 as a faint patch of light. M 3 is one of the brightest globulars in the night-sky. It looked like a small nebulous circle of light about 10' in diameter. Averted vision made it slightly bigger. The centre was slightly brighter than the outer parts, but there where no individual stars resolved. It didn't look grainy.

In the sketch above I included some field stars just for getting the orientation right. Not all stars visible were included. The faintest star, just northwest of M 3, is of magnitude 9.8. For more details on M 3, and a downloadable finder chart, see "The Deepsky TOP 100 nr. 9: M 3" in the Deepsky section on this site)