It was discovered on May 3, 1764,[10] and was the first Messier object to be discovered by Charles Messier himself. Messier originally mistook the object for a nebula without stars. This mistake was corrected after the stars were resolved by William Herschel around 1784.[11] Since then, it has become one of the best-studied globular clusters. Identification of the cluster's unusually large variable star population was begun in 1913 by American astronomer Solon Irving Bailey and new variable members continue to be identified up through 2004.[12]
Visibility
Many amateur astronomers consider it one of the finest northern globular clusters, following only
This cluster is one of the largest and brightest, and is made up of around 500,000 stars.[11] It is estimated to be 11.4 billion years old.[8] It is centered at 32,600 light-years (10.0 kpc) away from Earth.[14]
Messier 3 is quite isolated as it is 31.6
Oosterhoff type I cluster, which is considered "metal-rich". That is, for a globular cluster, Messier 3 has a relatively high abundance of heavier elements.[15]
13h 42m 11.23s, 28° 22′ 31.6″![{\displaystyle {\begin{smallmatrix}\left[{\ce {Fe}}/{\ce {H}}\right]\end{smallmatrix}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/4c0821bd80891e071c08e7c7ee8e022baedf522c)
