M103 (NGC 581)
Also known as M103 · M 103 · NGC 581
M103 (NGC 581) is an open star cluster in the constellation Cassiopeia, about 7,180 light-years from Earth.
Facts
| Type | Open star cluster |
|---|---|
| Constellation | Cassiopeia |
| Position (J2000) | 1h 33m 21s, +60° 39′ |
| Distance | 7,180 light-years (its light set off about 7,180 years ago) |
| Brightness | magnitude 7.4 (smaller is brighter; the faintest stars the eye sees are about 6) |
| Size on the sky | 7.4′ × 7.4′ (the full Moon is about 31′) |
| Filter | No filter (It shines in starlight of every colour, so a nebula filter would only dim it; a dark sky helps more.) |
| Studied in | 212 scientific papers (SIMBAD) |
When and how to see it
M103 (NGC 581) is highest in the sky at midnight in October. From India (about 20° N) it climbs to about 49° above the horizon; from 50° N, to about 79°. To see it you need binoculars.
Heights are worked out for India and for 50° N. Set your location in Settings to see them for where you are.
For tonight's best time from your own town, the darkness and the Moon, open it on the map and see its "Tonight from your location" card.
More in Cassiopeia
- Bubble Nebula
- Cassiopeia A
- Fish Head Nebula
- Heart Nebula
- M52 (NGC 7654)
- Pacman Nebula
- Soul Nebula
- Tycho's Supernova
Everything in Cassiopeia · All 88 constellations · All sky objects
Data: SIMBAD (CDS, Strasbourg; the site's weekly copy) · OpenNGC · Data sources & credits