Also Known As: H.VII.49, Cr 17, Lund 51, OCl 329, C0139+637
Object Type: Open Cluster
Right Ascension (2000.0): 01h 43m 03.1s
Declination (2000.0): +64° 02' 12"
Trumpler Type: I 2 m
Distance: 6,900 light years
Discovery: William Herschel, 9 November 1787 (18.7" reflector)
NGC Description: Cl, pS, B & vF st
Telescope: Parks Astrolight EQ6 • 6" f/6 Newtonian Reflector
Eyepiece/Magnification: 7.5mm Parks Gold Series Plössl • 120x • 26' FoV
Date/Time: 16 November 2009 • 05:45-06:30 UT
Observing Location: Oakzanita Springs, San Diego Co., CA
Transparency: NELM 6.4, TLM 14.2
Seeing: Pickering 7-8
Conditions: Clear, cold, dry, some wind
NGC 637 is a small, but surprisingly distinct open cluster located just over 1 degree northwest of Epsilon Cassiopeiae, the easternmost star of the famous "W" asterism. This cluster is strongly condensed with a prominent pair of 10th and 11th magnitude stars at the center of the cluster, designated Struve I (1st supplement) 264 (10.2, 11.4; 9.0"; 352°; both white). Numerous companions, both bright and very faint (as the NGC put it), surround this pair. Outliers streaming away in graceful arcs to the north and west give this cluster an aesthetically pleasing crescent shape. The cluster is followed by a wide pair of 11th magnitude stars located about 3' to the east. The brightest field star in the 26' field of view provided by the 7.5mm Plössl is 8th magnitude HD 10304, notable for its orange hue and lying 6½' to the SSW. William Herschel discovered this cluster with his 18.7" speculum metal reflector on November 9, 1787.