NGC 663 (Caldwell 10) is an open cluster of stars located in the constellation Cassiopeia approximately 6,500 light years from the Earth[1]. The cluster is relatively bright with a listed magnitude of 7.1[1]. Under dark skies, the brighter stars may be viewed with the aid of binoculars[1]. NGC 663 is a young cluster with an age estimated to be between 20 and 25 million years[1,3]. The cluster lies in front of a large molecular cloud. This cloud obscures many of the field stars in and around NGC 663[1,2]. The net effect of this is to make the cluster stars stand out in both visual observations and in astro-photo images.
NGC 663 is of scientific interest due to the large number of type Be stars[1,3]. These stars show prominent hydrogen lines in their spectrum[1]. A total of 24 such stars have been located in the cluster[1,3].
Two variable stars have been detected in NGC 663 [1,2]. These variable stars are likely eclipsing binaries with periods of .6 and 1.03 days[1].
The above image is orientated with north up and east to the left. Image integration and processing were accomplished using the software applications PixInsightTM and PhotoshopTM.
References
1Wikipedia: https://en.wikipedia.org/wiki/NGC_663
2G. Pietrzynski: https://articles.adsabs.harvard.edu/pdf/1996AcA....46..357P
3A. Pigulski, et al.: https://www.aanda.org/articles/aa/pdf/2001/34/aa10537.pdf