NGC 6633

Right Ascension	18 : 27.7 (h:m)
Declination	+06 : 34 (deg:m)
Distance	1.04 (kly)
Visual Brightness	4.6 (mag)
Apparent Dimension	27 (arc min)

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.

NGC 6633 has been discovered by the Swiss astronomer Philippe Loys de Cheseaux, according to the Webb Society Deep-Sky Observer's Handbook, Volume 3 (Open and Globular Star Clusters), p. 3. It was independently rediscovered by Caroline Herschel, and been included in her brother William's catalog as H VIII.72.

This magnificient object is contained in a large number of observing list, e.g. as No. "S11" in Paul Ahnert's Easy Object List, in the SAC 110 Best NGC List, No. 93 in the RASC Finest NGC Objects List, in John Caldwell's List and in the Astronomical League's Deep Sky Binocular Club List.

Last Modification: 29 Mar 1998, 12:20 MET