Open Star Cluster NGC 6939 in Cepheus

An 10 minute exposure with an ST-9E CCD camera thru Kopernik's 20-inch F/8.1 Ritchey Chretien Cassegrain telescope focal reduced to F/4. The field of view is about 17x17 arc minutes, with South at the top.

Dreyer's description of NGC 6939 in his New General Catalog (NGC):

"Cluster, pretty large, extremely rich in stars, westward compressed middle, stars of magnitude 11 to 16."

Quote from: The Deep Sky Field Guide to Uranometria 2000:

"Approximately 80 stars. Moderately rich in stars; small brightness range; slight central concentration."

• NGC 6939
• Magnitude: 7.8
• Constellation: Cepheus
• RA: 20h 31m 24.0s
• Dec: +60° 38' 00" Epoch 2000
• Size (mins): 8.0'
• Classification: Open Star Cluster.
  

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George Normandin, KAS

November 10th, 2001