Omega Centauri – NGC 5139

Omega Centauri is a globular cluster in the constellation of Centaurus, discovered by Edmond Halley in 1677 who listed it as a nebula. It was first recognized as a globular cluster by the James Dunlop from his observatory in Parramatta, NSW Australia in 1826.

Orbiting the Milky Way, it is the brightest and the largest known globular cluster associated with our galaxy. Of all the globular clusters in the Local Group of galaxies, only Mayall II in the Andromeda Galaxy is brighter and more massive. ω Centauri is so different from other galactic globular clusters that it is thought to be of different origin, and the thought is is that Omega Centauri may be the core of a dwarf galaxy which was disrupted and absorbed by our Milky Way galaxy.

Located about 15,800 light-years (4,850 pc) from Earth, it contains several million Population II stars, and stars in its center are so crowded that they are estimated to average only 0.1 light years away from each other. It is about 12 billion years old.

Omega Centauri is one of the few globular clusters visible to the naked eye and appears about as large as the full Moon.

Imaged from Bathurst, NSW Australia 1 July 2013 at 1900 hrs
Canon 7D – Prime Focus through Celestron CPC 9.25
ISO 1600
Exp. 20 sec x 30 frames in Deep Sky Stacker



4 thoughts on “Omega Centauri – NGC 5139

    1. It’s certainly one of the southern sky highlights … Similar to Andromeda for us down here though, it would be great to see it high in the sky rather than hugging the northern horizon.


      1. Yes, at 2 million or so ly, up here in NJ, M 31 is an easy naked eye object in a dark sky, high overhead, I’m guessing about the furtherest object we can see unaided. It’s companion galaxies are visible through a small telescope, NGC 205, a little more difficult.


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