Three Open Clusters in Cassiopeia

Here’s an image of three open clusters in all shapes and sizes (and colors) in the constellation of Cassiopeia. Top right we have NGC 654. NGC 654 is a brilliant colorful open cluster, discovered by William Herschel in 1787. This image shows many more features of this area. The dark serpent shaped area above the open cluster NGC 654 are “Lynds Dark Nebula” or LDN objects. Here we have three LDN objects 1332,1334,1337. Top left we have IC 166. IC 166 is an open cluster about 10,750 light years from us. Its age is estimated to be about 1.32 billion years and it is at the edge of a weak dark nebula. Its age plus the dust likely account for the rather red color of most of the stars in the cluster. Finally, at the bottom of this picture we see NGC 663. It has an estimated 400 stars and the brightest members of the cluster can be viewed with binoculars under dark skies. It is located about 6,900 light years distant with an estimated age of 20–25 million years so much younger than IC 166.

IC 166 (left), NGC 654 (right) and NGC 663 (bottom)

Telescope: 16″ f3.75 Dream Scope
Camera: FLI ML16803
Mount: ASA DDM85
Exposure: 3.5 hours  3x14x5min RGB
Acquistion: September 2021
Location: Southern Alps, France