Caldwell 81
Star cluster in Ara · 22,000 light-years
🔭 Explore Caldwell 81 in the 3D map →View Caldwell 81 images →| Type | Star cluster |
|---|---|
| Constellation | Ara |
| Right ascension | 17h 25m 29s |
| Declination | −48° 25′ |
| Object distance | 22,000 light-years |
| Apparent magnitude | 8.9 |
| Apparent size | 7.2′ (arc-minutes) |
| Approx. true diameter | 46.1 light-years across |
| Also known as | C81 · NGC 6352 |
Caldwell 81 is a star cluster (NGC 6352) in Ara — a family of stars bound by gravity. It appears as number 81 in the Caldwell catalogue, Sir Patrick Moore's 1995 list of 109 bright deep-sky objects for amateur astronomers. It spans roughly 7.2 arc-minutes on the sky. At about magnitude 8.9, it shows up in a small backyard telescope.
Although it appears about 7.2′ wide on the sky, its real span is roughly 46.1 light-years — the difference is a measure of how far away it lies.
Observing Caldwell 81
Caldwell 81 lies in the constellation Ara and is best placed in the evening sky around June. Its maximum altitude above the horizon depends on your latitude. It is best placed for observers in the southern hemisphere, and sits low for those far north. A small backyard telescope will show it; binoculars may hint at it under dark skies.
See Caldwell 81 in Universe Finder
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Sources
- Position, magnitude and angular size from the OpenNGC catalogue (Mattia Verga).
- Object identity cross-referenced with SIMBAD (CDS, Strasbourg).
- Image credits and the original observation source are linked with each photograph.
Related objects
- Pleiades — star cluster
- Hercules Cluster — star cluster
- Small Sgr Star Cloud — star cluster
- Messier 25 — star cluster
- Messier 103 — star cluster