Three lovely open clusters adorn this region of Cassiopeia, and show a variety of apparent sizes. In this image, spanning roughly 2 degrees 19 minutes by 1 degree 33 minutes, north is oriented to the left and east is toward the bottom.

The largest at upper right, spanning 16 minutes of arc, is NGC 663, a Trumpler Type II 3 r open cluster containing four 8th magnitude and ten 9th to 10th magnitude stars among its 400 members. The cluster is divided into two segments separated by a relatively star free zone oriented roughly N-S., with the larger eastern segment roughly twice as large as the smaller western segment. With an integrated visual magnitude of 7.1, this cluster could easily have been included in the Messier catalog. Also known as Caldwell 10 and Collinder 20, NGC 663 is a "young" cluster at a distance of 6,950 light years with an estimated age of 20-25 million years. Of interest, the cluster contains a high concentration of Be stars, with at least 24 identified to date.

At top center, intermediate in size, is NGC 654, a Trumpler Type II 2 6 open cluster spanning 5 minutes of arc. The cluster contains fifty 11th to 14th magnitude stars in a compact volume. The cluster's estimated age is 15 million years, even younger than its larger neighbor, and lies at a distance of 7,830 light years. In contrast to NGC 663, only 3 Be stars have been identified in NGC 654.

The smallest of the three clusters is IC 166, spanning just 4.5 minutes of arc and located just below center. It contains 120 stars and is a Trumpler Type III 1 r open cluster. IC 166 is also known as Lund 60, OCL-334, and Tombaugh 3., and lies at an estimates distance of 13,000 light years. Just 4 minutes or arc toward the west (top) is a wide double star consisting a bluish 9th magnitude primary and a yellowish 10th magnitude secondary, a beautiful color contrast pair among the rich start field.

Barely distinguishable at this plate scale, the open cluster Berkely 6 is located just below the two blue stars under NGC 663, and almost directly to the right of IC 166. Classified as a Trumpler Type II 2 p cluster, it forms an irregular grouping of about 20 stars , in an irregular band running from NE to SW, and lies at an estimated distance of 7,500 light years.

Several dark nebulae are faintly visible among the rich start field in this portion of Cassiopeia.