Messier 75
| Messier 75 | |
|---|---|
 | |
| 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] |
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.
References
- ^ Shapley, Harlow; Sawyer, Helen B. (August 1927), "A Classification of Globular Clusters", Harvard College Observatory Bulletin (849): 11–14, Bibcode:1927BHarO.849...11S.
- ^ a b c d "SIMBAD Astronomical Database". Results for NGC 6864. Retrieved 16 November 2006.
- ^ distance × sin( diameter_angle / 2 ) = 67 ly. radius
External links
- Messier 75 @ SEDS Messier pages
- Messier 75, Galactic Globular Clusters Database page
- Messier 75 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
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