Messier 75

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Messier 75
Messier 75 -hst11628 10 08723 43-Lasinh ABR555B438log.png
Observation data (J2000 epoch)
Class I[1]
Constellation Sagittarius
Right ascension 20h 06m 04.75s[2]
Declination −21° 55′ 16.2″[2]
Distance 67.5 kly[citation needed] (20.7 kpc)
Apparent magnitude (V) +9.18[2]
Apparent dimensions (V) 6′.8
Physical characteristics
Radius 67 ly[3]
Other designations M75, NGC 6864, GCl 116[2]
See also: Globular cluster, List of globular clusters

Messier 75 (also known as M75 or NGC 6864) is a globular cluster in the constellation Sagittarius. It was discovered by Pierre Méchain in 1780 and included in Charles Messier's catalog of comet-like objects that same year.

M75 is at a distance of about 67,500 light years away from Earth and its apparent size on the sky translates to a true radius of some 67 light years. It is classified as class I, meaning it is one of the more densely concentrated globular clusters known. The absolute magnitude of M75 is about −8.5 or some 180,000 times more luminous than the Sun.

Map showing location of M75

Messier 75 is part of the Gaia Sausage, the hypothesised remains of a merged dwarf galaxy.[4]


  1. ^ Shapley, Harlow; Sawyer, Helen B. (August 1927), "A Classification of Globular Clusters", Harvard College Observatory Bulletin (849): 11–14, Bibcode:1927BHarO.849...11S. 
  2. ^ a b c d "NGC 6864". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2006-11-16. 
  3. ^ distance × sin( diameter_angle / 2 ) = 67 ly. radius
  4. ^ C., Myeong, G.; W., Evans, N.; V., Belokurov,; L., Sanders, J.; E., Koposov, S. (2018). "The Sausage Globular Clusters". 

External links[edit]

Coordinates: Sky map 20h 06m 04.75s, −21° 55′ 16.2″