Messier 103
Star cluster in Cassiopeia · 8,500 light-years
🔭 Explore Messier 103 in the 3D map →View Messier 103 images →| Type | Star cluster |
|---|---|
| Constellation | Cassiopeia |
| Right ascension | 1h 33m 22s |
| Declination | +60° 39′ |
| Object distance | 8,500 light-years |
| Apparent magnitude | 7.4 |
| Apparent size | 4.5′ (arc-minutes) |
| Approx. true diameter | 11.1 light-years across |
| Also known as | M103 · NGC 581 |
Messier 103 is a star cluster (also catalogued as NGC 581) in Cassiopeia — a gravitationally bound family of stars sharing a common origin. It was recorded by Charles Messier in his famous catalogue of 110 deep-sky objects. It spans roughly 4.5 arc-minutes on the sky. At about magnitude 7.4, it is an easy target for binoculars and small telescopes.
Although it appears about 4.5′ wide on the sky, its real span is roughly 11.1 light-years — the difference is a measure of how far away it lies.
Observing Messier 103
Messier 103 lies in the constellation Cassiopeia and is best placed in the evening sky around October. Its maximum altitude above the horizon depends on your latitude. It sits far enough north to be circumpolar from mid-northern latitudes, and never rises for most of the southern hemisphere. It is a comfortable target for binoculars and small telescopes.
See Messier 103 in Universe Finder
Open the interactive 3D map to fly to Messier 103 and see it in context among the real stars around it. Launch the 3D view →
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 34 — star cluster