Globular Cluster Messier 68

Messier 68
Messier 68: Image taken with Hubble Space Telescope. © ESA/Hubble & NASA [245]


The globular cluster M 68 was discovered on 9 April 1780 by Charles Messier, who wrote: «Nebula without stars under the raven and the water snake; it is very weak, very difficult to see with the telescope; next to it is a star 6th magnitude.» [281] William Herschel wrote: «A beautiful star cluster, extremely rich and so compressed that most of the stars are mixed together. it is nearly 3' wide and about 4' long, but mostly round, and there are very few stars scattered around.» [217]

Physical Properties

The distance from M 68 is about 10.3 kpc (33'600 light years) and it is moving towards us at about 93 km/s. The mass is 223'000 times that of the sun. [251] 50 variables were found in the star cluster. [282] [282]

Revised+Historic NGC/IC Version 22/9, © 2022 Dr. Wolfgang Steinicke [277]
Designation NGC 4590
Type GCL (X)
Right Ascension (J2000.0) 12h 39m 28.0s
Declination (J2000.0) -26° 44' 32"
Diameter 11 arcmin
Visual magnitude 7.3 mag
Metric Distance 10.300 kpc
Dreyer Description globular, L, eRi, vC, iR, rrr, st 12
Identification, Remarks h 3404; GC 3128; M 68; GCL 20; ESO 506-SC30

Galaxy PGC 42334

The small, faint galaxy PGC 42334 is only about 10 arc minutes away.

«Catalogue of Principal Galaxies» Paturel et al., 1989 [144]
Designations PGC 42334: ESO 506-29, MCG 4-30-9
Right Ascension (J2000.0) 12h 39m 16.3s
Declination (J2000.0) -26° 54' 41"
Morphological Type SB
Dimensions 1.2' x 1.1'
Visual Magnitude 14.2 mag
Radial Velocity (HRV) 2976 km/s

Finder Chart

M 68 lies in the constellation Hydra. To find it, connect the stars Algorab (η Corvi) - Kraz (β Corvi) by 3.5 ° to the south. It is best seen from January to April.

Finder Chart Globular Cluster Messier 68
Globular Cluster Messier 68 in constellation Hydra. Charts created using SkySafari 6 Pro and STScI Digitized Sky Survey. Limiting magnitudes: Constellation chart ~6.5 mag, DSS2 close-ups ~20 mag. [149, 160]

Objects Within a Radius of 20°


  • [144] «An extragalactic database. I. The catalogue of principal galaxies.» Paturel, G.; Fouque, P. search by orcid; Bottinelli, L.; Gouguenheim, L.; Astronomy and Astrophysics, Suppl. Ser., Vol. 80, p. 299-315 (1989); Bibcode:1989A&AS...80..299P; (2021-02-18)
  • [149] SkySafari 6 Pro, Simulation Curriculum;
  • [160] The STScI Digitized Sky Survey;
  • [217] The Messier Catalog (SEDS); (2021-01-01)
  • [245] Bucking the trend; (2021-01-22)
  • [251] «Young Radio Pulsars in Galactic Globular Clusters» Jason Boyles, Duncan R. Lorimer, Phil J. Turk, Robert Mnatsakanov, Ryan S. Lynch, Scott M. Ransom, Paulo C. Freire, Khris Belczynski; The Astrophysical Journal, Volume 742, Number 1; DOI:10.1088/0004-637X/742/1/51
  • [277] «Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; (2021-02-17)
  • [281] «Catalogue Nébuleuses et des Amas D'Étoiles» Observées à Paris, par M. Messier, à l'Observatoire de la Marine, hôtel de Clugni, rue des Mathurins. «Connoissance des temps ou connoissance des mouvements célestes, pour l'année bissextile 1784 » Page 227; (2021-02-21)
  • [282] «A Census of Variability in Globular Cluster M68 (NGC 4590)» N. Kains, A. Arellano Ferro, R. Figuera Jaimes, D. M. Bramich, J. Skottfelt, U. G. Jørgensen, Y. Tsapras, R. A. Street, P. Browne, M. Dominik, K. Horne, M. Hundertmark, S. Ipatov, C. Snodgrass, I. A. Steele, K.A. Alsubai, V. Bozza, S. Calchi Novati, S. Ciceri, G. D'Ago, P. Galianni, S.-H. Gu, K. Harpsøe, T.C. Hinse, D. Juncher, H. Korhonen, L. Mancini, A. Popovas, M. Rabus, S. Rahvar, J. Southworth, J. Surdej, C. Vilela, X.-B. Wang, O. Wertz; arXiv:1502.07345v1; DOI:10.1051/0004-6361/201424600