Degree of difficulty 2 (of 5)

Minimum aperture 30mm

Designation NGC 5236

Type Galaxy

Class Sc

Distance 14.7 Mly (Cepheids, 2003)

Size 55,000 ly

Constellation Hydra

R.A. 13h 37.0min

Decl. –29° 52′

Magnitude 7.5

Surface brightness 22.1mag/arcsec2

Apparent diameter 12,9′×11,5′

Discoverer Lacaille, 1752

History M 83 was only the third galaxy discovery, after M 31 and M 32, when Nicholas Louis de Lacaille found it in 1751 or 1752 during his observing campaign at the Cape of Good Hope. His entry under number I.6 reads: “nebula without star, small and shapeless.” Messier, who knew Lacaille's catalog, finally managed to see this very southerly galaxy on the 17th of February 1881. He saw a “nebula without star, it appears as a faint and even light.”

The Australian observer James Dunlop described this galaxy in detail as his catalog number 62B: “A very beautiful round nebula, with an exceedingly bright well-defined planetary disk or nucleus, about 7″ or 8″ diameter, surrounded by a luminous atmosphere or chevelure [mane], about 6' diameter. The nebulous matter is rather a little brighter towards the edge of the planetary disk, but very slightly so. I can see several extremely minute points or stars in the chevelure, but I do not consider them as indications of its being resolvable, although I have no doubt it is composed of stars.” Dunlop probably glimpsed the many prominent star clusters in the spiral arms of M 83. William Lassell observed this galaxy from Malta. With a large aperture, he recognized it as a “three-branched spiral.” Most historical observers skipped M 83 because of its southerly position.

Curtis summarized the photographic appearance in 1918 very appropriately with the words: “A bright and unusually beautiful spiral. A large number of almost stellar condensations in the rather open whorls of this fine object.”

Astrophysics Undoubtedly, M 83 is one of the most beautiful spiral galaxies in the whole Messier catalog.