It was discobered by Jean-Dominique Maraldi in 1746 while he was estuding De Chéseaux comet. It was described as a nebulosa by Charles Messier when he inclueded it in his astronomical objects catalog, it wasn't until 1783 when William Herschel concreted M15 as a globular cluster.
This globular cluster is located 336000 light years from the earth, it's absolute magnitude is -9,2. It containes a elevated number of variable stars, 158 aprox. , 104 of them are type RR Lyrae.
I've analised M15 light spectrum and tried guess wich are the principal elements that form it
The scientifics K. Otsuki, S. Honda, W. Aoki, have also found vanadium abundances in M15.