Messier 15, also known as the Great Pegasus Cluster, is a globular cluster located in the northern constellation Pegasus. The cluster has an apparent magnitude of 6.2 and lies at a distance of 33,600 light years from Earth. Messier 15 is one of the oldest known globulars in our galaxy. It has an estimated age of 12 billion years and only 1 percent of the Sun’s iron content. The cluster has an absolute magnitude of -9.2, which makes it about 360,000 times more luminous than the Sun. Messier 15 is one of the most densely concentrated clusters of its kind with an exceptionally large number of stars orbiting what is likely a central black hole. The high density center is a result of the cluster having undergone a core collapse, a contraction of its core region. This is a common occurrence in globular clusters as they evolve. On the right half of this picture are clear traces of IFN (Integrated Flux Nebulae). IFN are a relatively recently identified astronomical phenomenon. In contrast to the typical and well known gaseous nebulas within the plane of the Milky Way galaxy, IFNs lie beyond the main body of the galaxy.
Messier 15 and some IFN
Telescope: 16″ f3.75 Dream Scope
Camera: FLI ML16803
Mount: ASA DDM85
Exposure: 6.5 hours (33x5min L + 3x11x5min RGB)
Date: August 2021
Location: Southern Alps, France
Bart Delsaert - Astrophotography 