Globular Cluster M75 (NGC 6864), class I, in Sagittarius

[m75.jpg]
Right Ascension 20 : 06.1 (h:m)
Declination -21 : 55 (deg:m)
Distance 57.7 (kly)
Visual Brightness 8.5 (mag)
Apparent Dimension 6.0 (arc min)
Discovered by Pierre Mechain
    1780

At a distance of nearly 60,000 light years, M75 is one of the more remote of Messier's globular clusters, lying well beyond the Galactic center. Some sources give even larger distances, up to as much as 100,000 light years ! (E.g., Burnham has 95,000, but W.E. Harris' database has it with 57,700 which we adopt here.) This would make it the most remote Messier globular, and the most remote galactic Messier object at all.

M75 is one of the more compact, concentrated globulars, classified as class I. Because of this and its distance, larger scopes are required to resolve it into stars. Its angular diameter of 6' corresponds to a linear extension of well over 100 light years, and it is of high luminosity, perhaps about 160,000 times that of the Sun (Mag -8.3).

Messier observed M75 on October 18th, 1780 "It seemed to M. Messier ( speaking of himself) that it consists of only of very faint stars, but contains some nebulosity." " M. Mechain described it as a nebula without stars." Charles Messier from his catalogue

Courtesy www.seds.org