M13: The Great Globular Cluster in Hercules
4.08.2022

In 1716, English astronomer Edmond Halley noted, "This is but a little Patch, but it shows itself to the naked Eye, when the Sky is serene and the Moon absent." Of course...

The Double Cluster in Perseus
8.10.2021

This pretty starfield spans about three full moons (1.5 degrees) across the heroic northern constellation of Perseus. It holds the famous pair of open star clusters, h and Chi Persei. Also cataloged...

Centaurus Galaxy Cluster in X Rays
28.03.2002

The Centaurus Cluster is a swarm of hundreds of galaxies a mere 170 million light-years away. Like other immense galaxy clusters, the Centaurus Cluster is filled with gas at temperatures of 10 million degrees or more, making the cluster a luminous source of cosmic x-rays.

M45: The Pleiades Star Cluster
1.09.2019

Have you ever seen the Pleiades star cluster? Even if you have, you probably have never seen it as dusty as this. Perhaps the most famous star cluster on the sky, the bright stars of the Pleiades can be seen without binoculars from even the depths of a light-polluted city.

Blue Straggler Stars in Globular Cluster M53
9.04.2012

If our Sun were part of M53, the night sky would glow like a jewel box of bright stars. M53, also known as NGC 5024, is one of about 250 globular clusters that survive in our Galaxy.

The Perseus Cluster of Galaxies
5.04.1996

Here is one of the largest objects that anyone will ever see on the sky. Each of the fuzzy blobs in the above picture is a galaxy, together making up the Perseus Cluster, one of the closest clusters of galaxies.

APOD: 2008 April 2- Globular Cluster M55 from CFHT
2.04.2008

The fifty-fifth entry in Charles Messier's catalog, M55 is a large and lovely globular cluster of around 100,000 stars. Only 20,000 light-years away in the constellation Sagittarius, M55 appears to earth-bound observers to be nearly 2/3 the size of the full moon.

Star Cluster NGC 362 from Hubble
11.10.2017

If our Sun were near the center of NGC 362, the night sky would glow like a jewel box of bright stars. Hundreds of stars would glow brighter than Sirius, and in many different colors.

Comet Hartley Passes a Double Star Cluster
26.10.2010

Most star clusters are singularly impressive. Open clusters NGC 869 and NGC 884, however, are doubly impressive. Also known as "h and chi Persei", this unusual double cluster, shown above, is bright enough to be seen from a dark location without even binoculars.

M3: Inconstant Star Cluster
15.04.2007

Star clusters appear constant because photographs of them are frozen in time. In reality, though, cluster stars swarm the center and frequently fluctuate in brightness. Although the time it takes for stars to cross...