Photograph of Omega Centauri, a globular cluster in Centaurus.

Omega Centauri

STAR CLUSTERGlobular cluster
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OVERVIEW

] STAR CLUSTER

Omega Centauri is a globular cluster in the constellation Centaurus, 17 700 from Earth, shining at apparent magnitude 5.33 (). It is catalogued as C 80, HD 116790 and C 1323-472, among 6 designations in total. It has been known since antiquity.

The largest and brightest globular cluster orbiting the Milky Way, holding ten million stars of several different ages — most likely the stripped core of a dwarf galaxy the Milky Way ate.

WHAT IT IS
Globular cluster
HOW FAR
17 700

The light arriving now left it that long ago.

HOW BIG ON THE SKY
27.0

About as wide as the full Moon.

HOW BRIGHT (V)

Bright enough for the naked eye, under a sky dark enough.

WHERE TO LOOK
Centaurus

The patch of sky it sits in, as seen from Earth.

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IMAGES

] 2 FRAMES
  • Chuck Ayoub
    CC0
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OBSERVING

] FROM WHERE YOU ARE

What it takes to see Omega Centauri for yourself. Everything in this part of the page is worked out for a real horizon, a real night and the equipment you say you have.

TONIGHT

Say where you are, and this line says when Omega Centauri is worth going out for.

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THROUGH AN EYEPIECE

] 150 MM TELESCOPE · 25 MM EYEPIECE
NE
FIELD 1.08°

Bright enough to see with your eyes alone, once you are away from town lights. Omega Centauri covers 27.0′ of sky against a of 1.08°, so at 48× it is comfortably framed.

48×
1.08
1.25
13.0
SIZE ON THE SKY
27.0
FILLS OF THE FIELD
42% of the width
APPARENT MAGNITUDE ()
5.33 · within reach

Omega Centauri is not a point of light, so the limit above is the wrong one to hold it against: the same brightness spread over 27.0′ of sky is harder than a star of it, and goes first. Catalogued sizes are measured to a photographic contour, and the part an eye sees is usually smaller.

FIND IT ON THE SKY MAP ↗
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APPARENT PLACE

] EQUINOX J2026.7

Where a telescope has to be pointed today, which is not quite where the catalogue records the object: the coordinate grid itself has turned since the year 2000 the catalogue is referred to.

RIGHT ASCENSION
DECLINATION
GRID TURNED SINCE
18.3
PROPER MOTION SINCE
none published

Computed for 2026-08-27 00:00 UT. No proper motion is published for Omega Centauri, so nothing here moves the object; what separates this from the catalogued position above is the coordinate grid turning under it — about fifty arcseconds a year of precession since 2000, and the small nodding of the Earth’s axis on top of that. Aberration and refraction are not included, and neither is parallax; each is under an arcminute, which is also about as well as the catalogued position is known. The same figure for any date.

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CATALOG DATA

] 10 FIELDS

The raw catalogue values, as the source published them, with the error bars where one was published — sorted by what each set of figures is about rather than by the order they happened to be stored in.

HOW BRIGHT IT IS

What the light adds up to, measured through one filter at a time. A magnitude is a brightness on a backwards scale — the smaller the number, the brighter the object.

Apparent magnitude ()
Apparent magnitude ()

WHERE IT IS AND HOW IT MOVES

Position, motion across the sky and the size it covers on it. These are measurements of the object as seen from here, so every one of them depends on where here is.

Radial velocity
234
Redshift (z)
Major axis
27

WHEN IT WAS FOUND

Who first saw it, from where, and by what method.

Discovered by
Edmond Halley

OTHER NAMES AND NUMBERS

The identifiers other catalogues file this object under, for anyone joining this data to theirs.

OpenNGC type code
GCl
Wikidata item
Q14275
Wikipedia article
Omega Centauri

WHERE THESE FIGURES CAME FROM

Which catalogue, paper or model each of the fields above was read from, where the source named one.

Distance catalogue entry
NGC 5139
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ALSO KNOWN AS

] 6 DESIGNATIONS
  • Caldwell C 80
  • Common name ω Centauri
  • HD HD 116790
  • IAU cluster C 1323-472
  • MWSC MWSC 2120
  • NGC NGC 5139
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LOOK IT UP ELSEWHERE

] 3 SERVICES

Each link carries the identifier printed beside it. Nothing on this page is a measurement of our own, so a number that disagrees with one of these is worth reporting — and a service that has never catalogued this object under this name will say so plainly.

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CITE THIS PAGE

] DR1

This page is live and its numbers move when an upstream refreshes, so the citation names the release the rows belong to rather than the day you read them. The release itself is frozen, republished as a bundle, and is what a data-availability statement should point at.

PLAIN TEXT
SpaceCatalog. Omega Centauri [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ngc-5139
BIBTEX
@misc{spacecatalog_ngc-5139,
  author       = {{SpaceCatalog}},
  title        = {{Omega Centauri}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/ngc-5139},
  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from OpenNGC.}
}

The values above were taken from OpenNGC — CC-BY-SA-4.0. Citing this page does not replace citing that catalogue, and its licence is share-alike: the terms reach whatever you build from these rows.

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