NGC 6633 is an open cluster, in the constellation Ophiuchus. Discovered in 1745-46 by Philippe Loys de Chéseaux and independently rediscovered by Caroline Herschel, and catalogued 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.
Images by Neil Webster
Altair Astro 115 APO, NEQ6, Canon 600D, ZWO AS1385 MC, ISO 800, f/7
Exposure 47x 120s
St Marys Platt, England