Globular Star Cluster M-30 (NGC 7099) in Capricornus

Description of M-30 in The Deep Sky Field Guide to Uranometria 2000 (c) Willmann-Bell, Inc.:

Brightest stars = magnitude 12.1
horizontal branch stars magnitude = 15.1
Concentration: 5 (scale 1{dense} to 12{loose})


Charles Messier (August 3rd, 1764): 'Nebula discovered near 41 Capricorni (Flamsteed). Seen with difficulty in 3.5-foot telescope. Round, contains no star. Found from x Capricorni. Reported on chart of comet of 1759. Diam.2' Hand written notes in Messier's copy of his catalog include the following: "Seen only with difficulty in an ordinary telescope of 3.5-feet. It is round and I saw no star there having observed it with a good Gregorian telescope of 104x"

W. Hershel (1783): '(Resolved into)..'a brilliant cluster with two rows of stars, 4 or 5 in a line which probably belong to it.'

Admiral Smyth: 'A fine, pale white cluster. This object is brighter and from the straggling streams of stars on its N edge, has an elliptical aspect with a central blaze: few other stars in the field.'

Dreyer's description of NGC 7099 in his New General Catalog(NGC): "Remarkable!, globular cluster, bright, large, little extended, gradually westward much brighter middle, stars of magnitude 12 to 16."

Several sources give the distance to M-30 as about 40,000 light years, and at that distance the true diameter would be 100 light years. But Click here for the latest news on Globular Star Cluster distances and ages!!

• M-30, NGC 7099
• Magnitude: 7.5
• Constellation: Capricornus
• RA: 21h 40' 23.9"
• Dec: -23° 11' 00" Epoch 2000
• Size: (mins) 11
• Classification: Globular Cluster
  

George Normandin, KAS

November 13th, 2009