IC 4665
August 2010 :
During the summer of 1977, I was thumbing through the pages of the July issue of Astronomy. I came across a photograph of the constellation Ophiuchus and noticed what appeared to be a nice open star cluster a degree or two north of beta (β) Ophiuchi. A check of Norton’s Star Atlas showed just a single star in that location. Intrigued, I decided to go outside and look for myself. Lo and behold, my 8X50 binoculars revealed a beautiful open cluster about a degree across and containing some two dozen stars. To me, it resembled the Praesepe Cluster in Cancer.
I sent a description of the mystery cluster to “Deep Sky Wonders” columnist Walter Scott Houston. He wrote back, informing me that my “discovery” was, in fact the open star cluster IC 4665. It wasn’t plotted on my copy of Norton’s, an omission rectified in more recent editions.
One reason for IC 4665’s relative anonymity is its large size, allowing it to elude the narrow fields of large-aperture telescopes. Charles Messier and William Herschel missed it, and it wasn’t included in the New General Catalogue. This often-overlooked cluster is definitely a must-see object for binoculars and rich-field telescopes.
Your comments on this column are welcome. E-mail me at gchaple@hotmail.com
.
