IC 2391

IC 2391
IC 2391
Observation data (J2000.0 epoch)
Right ascension	08h 40.6m
Declination	−53° 02′
Distance	574 ly (176 pc)
Apparent magnitude (V)	2.5
Apparent dimensions (V)	50′
Physical characteristics
Other designations	Caldwell 85, Cr 191, C 0838-528, Lac II 5
Associations
Constellation	Vela
	See also: Open cluster, List of open clusters

IC 2391 (also known as the Omicron Velorum Cluster or Caldwell 85) is an open cluster in the constellation Vela consisting of hot, young, blueish stars, some of which binaries and one of which is a quadruple. Persian astronomer A. a.-R. al-Sufi first described it as "a nebulous star" in c. 964.^[2]^[3] It was re-found by Abbe Lacaille and cataloged as Lac II 5.

It is centred about 490 light-years away from Earth and can be seen with the naked eye. It contains about 30 stars with a total visual magnitude of 2.5, spread out along 50 arcminutes.

^ "IC 2391". sim-id. Retrieved 2020-06-11.
^ Deep-sky Observer's Handbook: Open and globular clusters, Kenneth Glyn Jones, Webb Society (1979), at p3
^ The History of Astronomy, 2017, Anne Rooney, at p162

[1] "IC 2391". sim-id. Retrieved 2020-06-11.

[2] Deep-sky Observer's Handbook: Open and globular clusters, Kenneth Glyn Jones, Webb Society (1979), at p3

[3] The History of Astronomy, 2017, Anne Rooney, at p162

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IC 2391

Observation data (J2000.0 epoch)
Right ascension	08^h 40.6^m
Declination	−53° 02′
Distance	574 ly (176 pc^[1])
Apparent magnitude (V)	2.5
Apparent dimensions (V)	50′
Physical characteristics
Other designations	Caldwell 85, Cr 191, C 0838-528, Lac II 5
Associations
Constellation	Vela
See also: Open cluster, List of open clusters