Messir 15 is a globular cluster in the costellation of Pherseis. At an estimated 12.0 billion years old, it is one of the oldest known globular clusters.
M15 is about 33,600 light years from Earth, and 175 light years in diameter. It has an absolute magnitude of -9.2, which translates to a total luminosity of 360,000 times that of the Sun. Messier 15 is one of the most densely packed globulars known in the Milky Way Galaxy. Its core has undergone a contraction known as ‘core collapse’ and it has a central density cusp with an enormous number of stars surrounding what may be a central black hole.
Home to over 100,000 stars, the cluster is notable for containing a large number of variable stars (112) and pulsars(8), including one doubleneutron star system, M15 C. M15 also contains Pease1 , the first planetary nebula discovered within a globular cluster in 1928. Just three others have been found in globular clusters since then.
- Costellation: Pegasus
- AR: 21h 29m 58.38s – DEC: +12° 10′ 00.6″
- Distance: 33.600 ly
- Age: —
- Optics: Takahashi FSQ85ED
- Mount: EQ6 Skywatcher
- Camera: QSI 683 WSG-5
- Accessories: Lodestar, USB_Focus V3
- Cooling: -20°C
- Filters: Astrodon Tru-Balance E-Series Gen 2 HaLRGB
- Exposure: RGB bin1 300″ [15x15x16]
- Flat-Dark-Bias: 15-19-201
- Integration: 3.8 h
- Date: Aug 18/20th, 2018
- Location: Own remote observatory
- SQM-L: 21.10
- Software: PHD2, Voyager, Pixinsight, PS