Globular Cluster M 3

M 3 — a globular cluster in the constellation Canes Venatici, one of the largest and brightest: it consists of more than 500,000 stars. It is located at a distance of 33,900 light-years from Earth.

It was discovered by Charles Messier on May 3, 1764; initially considered a nebula, but in 1784 William Herschel resolved the cluster into individual stars. In 1913, Solon Irving Bailey began studying the variable stars within it.

The best time for observation in the mid-latitudes of the northern hemisphere is spring and summer. Its apparent magnitude is 6.4m. Under clear, moonless skies away from cities, it can be seen with the naked eye by people with good vision. It is easy to find with binoculars (halfway from α Canum Venaticorum to Arcturus — α Boötis). In a 150 mm telescope, it already appears as a ball of nearly a hundred stars.