Globular cluster · Centaurus

NGC 5139 Omega Centauri

Also known as: C80

mag 3.936′ across

About

NGC 5139 (Omega Centauri) is a globular cluster of magnitude 3.9 in Centaurus, about 36′ across.

NGC 5139 is in the constellation Centaurus.
Best evenings: around late May it is highest at about 9 pm (10 pm in summer time); a month earlier, two hours later.
Where on Earth: it is seen well, at least 10° up, from south of 33° N.
Southern Cross and the Pointers: The biggest globular cluster of the Milky Way, a fuzzy star to the eye 14° north-west of Hadar.

When it rises and sets tonight, how high it climbs and how much the Moon gets in the way are worked out in your browser for your place.

EyesA fuzzy “star” — it even has a star name, ω Centauri. Easy from the southern hemisphere.
Binoculars (10×50)A large, bright fuzzy ball.
Telescope (6–8 inch)Thousands of stars across a field as wide as the full Moon — the finest globular cluster in the sky.

For a dark country sky with no Moon. From a city, faint galaxies and nebulae can disappear completely.

Designations	NGC 5139, C80
Type	Globular cluster
Magnitude	3.9The smaller the number, the brighter.
Apparent size	36′the full Moon is 31′ across
Surface brightness	≈ 20.3 mag/arcsec²Estimate from the magnitude and size, per square arcsecond.
Constellation	Centaurus
Right ascension (J2000)	13h 26m 45.9s
Declination (J2000)	−47° 28′ 37″