This image captures many star clusters, reflection nebulae and dark nebulae located in the constellation of Cassiopeia at a declination of +61 degrees.

Here are a few of my favorite objects in this image.  Refer to the annotated mouseover image for help in identifying each object:

- The winding dark nebula at the top of the image consists of 3 objects - LDN 1332, LDN 1334, and LDN 1337. The dark nebula is one continuously flowing shape although it has been given 3 separate Lynds Dark Nebula designations. Beverly Turner Lynds was an American astronomer who, 50 years ago, created the Lynds Bright Nebulae (LBN) and Lynds Dark Nebulae (LDN) catalogs based on her visual review of the Palomar Sky Survey.

- The large open cluster just below the winding dark nebula is NGC 654. This cluster has about 80 stars and is about 10,000 light years away. The small, faint reflection nebula towards the bottom right of the cluster is VdB 6.  This cluster surrounds the bright 7th magnitude yellowish supergiant star HD 10494, which is believed to be part of the cluster.  Because of this bright star, this is the brightest cluster in the image and the only one at magnitude 6 (6.5 to be exact).  To my eyes, some of the other clusters in the image look slightly brighter.  

- The most famous star cluster here is the magnitude 7.4 cluster M103, in the bottom right corner of the image.  This open star cluster is almost 10,000 light years away. Almost 200 stars comprise this cluster, which is about 20 light years in diameter. Bright blue stars highlight this open cluster, with a few orange stars including the one giant towards the center. Of all of the Messier open star clusters, M103 is one of the smallest, youngest and most remote.

- The largest (in apparent size) cluster here is NGC 663, at the left center of the image.  This magnitude 7.1 open cluster of 400 stars is located 7000 light years away. It is 12 arc-minutes in width and 25 light years in diameter.

- The somewhat dimmer magnitude 7.9 cluster at the bottom center of the image is NGC 659.  This open cluster is located 8000 light years away. The cluster spans 6 arc-minutes in our apparent view, which corresponds to a diameter of 14 light years.

- The most visually interesting cluster in the image for me is also one of the dimmest – the magnitude 11.7 orange open cluster IC 166, seen at upper left.  It is the most distant cluster here at 17,000 light years away.  It is also the largest in physical size, at 40 light years wide.

- The tightest cluster here is Trumpler 1, the small cluster at the right center edge.  This cluster is highlighted by a row of 4 bright stars in a diagonal row at the center of cluster.  3 of these 4 bright central stars are double stars.

While researching my RASA purchase, I realized its value in imaging faint nebulae when coupled with the full frame ASI6200 camera.  But I never dreamed that I would enjoy imaging star clusters so much with this setup as I did in this image, especially with such a short (100 minute) total integration time. I imaged a number of these objects previously with my refractor (for example, see M103, NGC 654, NGC 659, and NGC 663) but none with the same framing perspective and beauty that I enjoyed here.  Some of the bright stars appear a bit funky in their shape here due to the RASA, especially along the image edges, but I am willing to give that up for the other benefits.