Degree of difficulty 2 (of 5)

Minimum aperture 30mm

Designation NGC 5024

Type Globular cluster

Class V

Distance 61,270 ly (R2005)

Size 230 ly

Constellation Coma

R.A. 13h 12.9min

Decl. +18° 10′

Magnitude 7.7

Surface brightness –

Apparent diameter 13′

Discoverer Bode, 1775

History M 53 was discovered in the early morning hours of the 3rd of February 1775 by Johann Elert Bode in Berlin (Germany). Bode described it as “lively and round.” Charles Messier had no knowledge of Bode's observation and discovered M 53 independently on the 26th of February 1777 as a “nebula without stars.” He later likened it to M 79 and commented: “round and conspicious.”

Only a few years later, William Herschel succeeded with his fine, home-made reflectors in resolving this globular cluster into individual stars. He likened M 53 to M 10 and wrote enthusiastically: “One of the most beautiful objects I remember to have seen in the heavens. The cluster appears under the form of a solid ball, consisting of small stars, quite compressed into one blaze of light, with a great number of loose ones surrounding it, and distinctly visible in the general mass.” On the 14th of March 1783, he discovered the neighboring, but much fainter, globular cluster NGC 5053.

“A most beautiful, highly compressed cluster” was the comment on M 53 made later by John Herschel. He stated the brightness of its individual stars as magnitudes 12 to 20 and said that the visual appearance would be “indicating a round mass of pretty equable density.”

Lord Rosse was under the impression that M 53 was “not compressed to one point but apparently to four or five different points within a small area,” and he gave a diameter of only 3'. Photographic images, however, instead suggest 10', according to Curtis.

Astrophysics M 53 has the quite large distance of about 63,000 light-years from us, as well as from the galactic center.