Winter Cluster Challenge

Washed-out Astronomer — Mon, 01 Mar 2010 01:26:25 +0000

M35 and M38 are two beautiful open clusters that are well positioned for observing during the winter months. M35 is located in western Gemini, just a few degrees north and west of η Geminorum. It is a big cluster spread across an area nearly the size of the full moon. At magnitude 5.3 overall, and with nearly a hundred stars of 7^th through 11^th magnitude, M35 is an easy target even in heavily light polluted skies. Smaller and fainter at magnitude 7.5 overall, M38 is also a beautiful object. It consists of about a hundred stars, with the brightest ones forming a very distinctive letter “π” that is clearly visible even with small telescopes (you can see the “π” upside down in the photo to the right).

While these clusters are quite beautiful and easily observed from washed-out skies, there is something that sets them apart from the other many bright open clusters visible in the winter skies: both of these have fainter clusters within the same field of view. The combination of two clusters in one field of view makes them a particularly interesting sight. Because these fainter clusters are at the edge of visibility for urban observers, they make great challenge objects when observing in washed-out skies. I have more information for those of you wanting to take up this challenge....

Photos of M38 (upper, with NGC 1907 at the bottom edge) and M35 (lower, with NGC 2158 at the bottom-right edge) courtesy of Land of Oz Observatory.

Open clusters

Winter Cluster Challenge