Messier 15

Messier 15 is host an intermediate-mass black hole at its core.


33,600 light-years

Apparent Magnitude




object type

Globular Cluster

Hubble view of M15
This cluster of stars is known as Messier 15, and is located some 35 000 light-years away in the constellation of Pegasus (The Winged Horse). It is one of the oldest globular clusters known, with an age of around 12 billion years. Both very hot blue stars and cooler golden stars can be seen swarming together in the image, becoming more concentrated towards the cluster's bright centre. Messier 15 is one of the densest globular clusters known, with most of its mass concentrated at its core. As well as stars, Messier 15 was the first cluster known to host a planetary nebula, and it has been found to have a rare type of black hole at its centre. This new image is made up of observations from Hubble's Wide Field Camera 3 and Advanced Camera for Surveys in the ultraviolet, infrared, and optical parts of the spectrum.

A spectacular swarm of stars, M15 was discovered in 1746 by Jean-Dominique Maraldi, an Italian astronomer on the hunt for comets. This globular cluster is one of the densest ever discovered, with very hot blue stars and cooler orange stars becoming more concentrated toward its bright core. M15 is located in the constellation Pegasus 33,600 light-years from Earth. Shining with an apparent magnitude of 6.2, the cluster can be spotted with a pair of binoculars. The best time to observe it is in October.

Hubble view of M15
This Hubble image of M15 provides a wider view of the cluster. The glowing blue blob toward the bottom left of the cluster’s core is the planetary nebula Pease 1.
ESA/Hubble & NASA

M15 was the first globular cluster known to host a planetary nebula (the gaseous shell of a dying star). This nebula, Pease 1, was detected in 1928 by Francis G. Pease and is one of only four planetary nebulas known to exist within a globular cluster. In this image, Pease 1 appears as the large, bright blue object to the left of the cluster’s center.

This cluster is host a rare type of black hole at its center: an intermediate-mass black hole. Supermassive black holes are found at the center of galaxies and can be billions of times more massive than the sun. More diminutive “stellar” black holes, on the other hand, are on the order of 10 solar masses. The black hole thought to exist at the center of M15, however, is 4,000 times the mass of the sun.

Hubble captured this image of M15’s core using observations in visible, infrared and ultraviolet light.

For more information about Hubble’s observations of M15, see:

locator star chart for M15
This star chart for M15 represents the view from mid-northern latitudes for the given month and time.
Image courtesy of Stellarium

Explore Hubble's Messier Catalog

The following pages contain some of Hubble’s best images of Messier objects.

Bright green, orange, and yellow tendrils intertwined within this egg shaped nebula.

Messier 1 (The Crab Nebula)

Better known as the Crab Nebula, Charles Messier originally mistook Messier 1 for Halley’s Comet, which inspired him to create…

A Hubble image of a ball of thousands of stars

Messier 2

Hubble's image of Messier 2 is comprised of visible and infrared wavelengths of light.

Hubble view of M3 - a ball of thousands of stars.

Messier 3

Messier 3 holds more than 500,000 stars.