| Description | M15 was discovered by Jean-Dominique Maraldi in 1746 while observing a comet. Maraldi, who also discovered M2, lived in Paris and was a member of the French Academy. It was recorded by Messier on June 3, 1764: "Nebula without a star... it is round, in the center it is brilliant." Like so many others, the first observer to note individual stars was William Herschel in 1783.<--> M15 is ranked 6th in brightness and 8th in diameter among Messier GC's. It has a distinctive floral character, more like an Aster than a rose: the brightest part of the core represents the disk floret, while the slowly dimming cluster represents the rays. Unlike M5, there does not seem to be a significant halo beyond the globular cluster itself. It is somewhat oblate if you measure only the bright core, with a ratio between 1.1 and 1.2. |
