Messier 3

NGC 5272
Observation data (J2000 epoch)
Class	VI
Constellation	Canes Venatici
Right ascension	13h 42m 11.23s[1]
Declination	28° 22′ 31.6″[1]
Distance	33.9 kly (10.4 kpc)
Apparent magnitude (V)	+6.2[1]
Apparent dimensions (V)	18′.0
Physical characteristics
Mass	245,000 M☉ (4.87 x 1035 kg)
Radius	90 ly
Estimated age	8 x 109 years
Other designations	NGC 5272[1]
See also: Globular cluster, List of globular clusters

Messier 3 (also known as M3 or NGC 5272) is a globular cluster in the constellation Canes Venatici. It was discovered by Charles Messier in 1764, and resolved into stars by William Herschel around 1784. This cluster is one of the largest and brightest, and is made up of around 500,000 stars. It is located at a distance of about 33,900 light-years away from Earth. M3 has an apparent magnitude of 6.2,^[1] making it a difficult naked eye target even with dark conditions. With a moderate-sized telescope, the cluster is fully defined. It is estimated to be 8 billion years old. It is pretty difficult to spot this object in an amateur telescope without GoTo as it has no nearby pointer stars; though it is almost exactly halfway between and on a line connecting Cor Caroli with Arcturus.

Arcturus can be used to help locate M3

Messier 3 with amateur telescope

External links

• SEDS Messier pages on M3
• M3, Galactic Globular Clusters Database page
• M3 Photo detail Dark Atmospheres
• Messier 3 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

References

1. ^ ^{a b c d e} "Messier 3". SIMBAD Astronomical Database. http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Messier+3. Retrieved 2006-11-15. 

Coordinates: 13^h 42^m 11.23^s, +28° 22′ 31.6″