C91
NGC 3532
Object Data
- Catalog Designation
- C91
- Type
- OpenCluster
- Constellation
- Carina
- Magnitude
- 3.0
- Right Ascension
- 11h 05m 29.5s
- Declination
- -58° 45' 18.0"
- Distance
- 1,300 light-years
- Angular Size
- 55
Survey Image
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About C91
Description
NGC 3532 is one of the brightest and richest open clusters in the sky, located in Carina about 1,321 light-years away. Spanning 55 arcminutes, it contains about 150 stars brighter than magnitude 12 and over 400 confirmed members. At magnitude 3.0, it is easily visible to the naked eye.
Observing Tips
A stunning cluster in binoculars and wide-field telescopes. The large angular size means low power is essential. Many colorful stars including orange giants contrast with blue-white members. John Herschel called it the most beautiful object in the sky. Best from southern latitudes in late winter and spring.
History
Discovered by Nicolas Louis de Lacaille in 1751 from South Africa. John Herschel described it glowingly during his southern sky survey from the Cape of Good Hope in the 1830s. It was the first target observed by the Hubble Space Telescope in 1990 for calibration.
Fun Facts
NGC 3532 was the very first object pointed at by the Hubble Space Telescope after its launch. Despite the telescope's initially flawed mirror, the cluster's stars helped engineers diagnose the spherical aberration problem. The cluster is about 300 million years old.
Community Photos (1)
Credit: ESO/G. Beccari. License: CC BY 4.0. (Wikimedia Commons)
Skybred Mar 2, 2026