NGC 6633

NGC 6633
Observation data (J2000.0 epoch)
Right ascension	18h 27.7m
Declination	6° 34′
Distance	1.04 kly
Apparent magnitude (V)	4.6
Apparent dimensions (V)	27′
Physical characteristics
Estimated age	660 million years
Other designations	NGC 6633, De Cheseaux No. 3 H VIII.72, Melotte 201, Collinder 380
See also: Open cluster, List of open clusters

NGC 6633 is an open cluster that was, according to the Webb Society Deep-Sky Observer's Handbook, Volume 3 (Open and Globular Star Clusters), p. 3, discovered in 1745-46 by Philippe Loys de Chéseaux. It was independently rediscovered by Caroline Herschel, and been included in her brother's catalog as H VIII.72.

This cluster is nearly as large as the full moon, and contains 30 stars which make it shine at a total magnitude of 4.6; the brightest star is of mag 7.6. Its age was estimated at 660 million years.

External links

• http://seds.org/messier/xtra/ngc/n6633.html
• NGC 6633 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Coordinates: 18^h 27^m 42^s, +06° 34′ 00″