Both are remarkably obvious even in a small telescope, just what's needed for urban and suburban stargazers. Trumpler 1 is a small but bright open cluster that mainly consists of two lines of stars. Put together, their arrangement led to this star cluster being dubbed "The Zipper" due to the brightest stars resembling the teeth on many a zipper found in everyday clothing. Although the poor seeing hid fainter stars lurking among the brighter members, at 227X I counted some 15 to 20 stars in this eight magnitude object. With an apparent size of some five arc-minutes, medium or high powers are best for this eye catching open cluster.
Sunday, January 6, 2013
Cassiopeia's starry treasures
Winter has been as usual cloudy and rainy so far in my area, but windows open in the weather that I make use of wherever possible. Last weekend before New Year's was no exception, and despite the very bright waning gibbous moon I rolled out the 15-inch into the driveway and went on the hunt. Because of the light pollution and interference from the moon, galaxies and faint nebulae were out of the question, but another class of deep sky objects not affected nearly as much was not. Open clusters when they are reasonably bright can penetrate the milky and light polluted skies enough to be observable from an urban area. So I looked up two of Cassiopeia the Queen's open clusters, Trumpler 1 and Markarian 6. I have repeatedly observed the Messier and NGC open clusters that showed themselves to my telescopes, but these objects I was unaware of until I read the January 2012 issue of Sky & Telescope magazine.