Messier 28 (also known as M28 or NGC 6626) is a w:globular cluster in the w:constellation Sagittarius. It was discovered by w:Charles Messier in w:1764.

Messier 28
Messier 28 by w:Hubble Space Telescope; 2.5′ view
Credit: w:NASA/w:STScI/w:WikiSky
Observation data (w:J2000 epoch)
Right ascension18h 24m 32.89s[1]
Declination-24° 52′ 11.4″[1]
Distance18.3 kly (5.6 kpc)
Apparent magnitude (V)+7.66[1]
Apparent dimensions (V)11′.2
Physical characteristics
Masskg ( M)
Radius30 ly[2]
Notable featuresContains pulsar
Other designationsM 28, NGC 6626, GCl 94[1]

M28 is at a distance of about 18,000 to 19,000 w:light-years away from w:Earth. 18 RR Lyrae type w:variable stars have been observed in this cluster. In w:1986, M28 became the first globular cluster where a millisecond pulsar was discovered (by the w:Lovell Telescope at w:Jodrell Bank Observatory).[3]

Messier 28 on w:2MASS; wide angle

External links


  1. a b c d "SIMBAD Astronomical Database". Results for NGC 6626. Retrieved 2006-11-16.
  2. distance × sin( diameter_angle / 2 ) = 30 ly. radius
  3. "JBO - Stars". w:Jodrell Bank Observatory. Retrieved 2007-06-01.