NGC 6946 is a large spiral galaxy, lying on the Cepheus – Cygnus border about two degrees southwest of the 3rd- magnitude star Eta Cephei. The galaxy is 11th magnitude, and appears nearly circular to the eye, measuring about 8′ in diameter.

Spiral Galaxy NGC 6946
Close-up of spiral galaxy NGC 6946. Gemini Observatory/Travis Rector

Many observers find this object difficult even with large telescopes, but personally I had no trouble seeing it with a 4.5-inch scope. I think that the key to success is observing from a location with very dark skies, because the galaxy has a low surface brightness even moderate light pollution will make it invisible.

Appearing in the same visual field, just 40′ northwest of NGC 6946 you will find NGC 6939, a dim open star cluster. Its eerie glow is partially resolved into stars at medium power, in the northern part of the cluster you will see three stars disposed in a triangle.

Apertures larger than ten inches will resolve the cluster completely, and NGC 6939 takes on a kite-like appearance with brighter stars defining a kite shape.

Finder map – field width 15 degrees, stars to magnitude 9.5.