NGC 206, seen here just left of the center of the image, is a large star forming region in one of the outer spiral arms of M31, the Andromeda Galaxy.

Also known as OB 78, this stellar association is made up of hot young type O and type B stars that are only 10 to 20 million years old. In his paper The Association OB 78 in the Andromeda Nebula in the Astronomical Journal, Sidney van den Bergh cataloged more than 100 of the brightest stars in NGC 206, measuring their brightness and color. Most are V magnitude 18 and 19. The brighter members, down to 19th magnitude, are seen in the center of the image above. The association contains more than 300 stars that are brighter than magnitude 21. The stellar association itself has a combined magnitude of 12.8, and is bright enough to be seen in moderately-sized amateur telescopes.

Almost all of the brighter stars in the above image are foreground stars that are members of our own Milky Way Galaxy that just happen to lie along the same line of sight as NGC 206. The fainter blue stars in NGC 206 are actually blue giants inside of M31 that are resolved at a distance of 2.5 million light-years away. Brighter background areas in the rest of the image are unresolved stars in the spiral arms of M31. Darker areas are obscuring dust lanes in M31 that block the light of stars behind them.

NGC 206 has an apparent diameter of 4.2 arcminutes and was cataloged as H V.36 by William Herschel on October 17, 1786.

North is to the top in the above image.

NGC 206 Catalogs: NGC 206 Object Type: Stellar Association Magnitude: 12.8 / Individual Stars Mag 18-19 Size: 4.2 Constellation: Andromeda Image Field Centered At: RA: 00h 40m 23s Dec: +40° 44' 50"