Open cluster · Cassiopeia
M103
Also known as: NGC 581
mag 7.46′ across
About
M103 is an open cluster of magnitude 7.4 in Cassiopeia, about 6′ across.
How to find it
- M103 is in the constellation Cassiopeia.
- Best evenings: around late November it is highest at about 9 pm (10 pm in summer time); a month earlier, two hours later.
- Where on Earth: it is seen well, at least 10° up, from north of 19° S.
- Cassiopeia’s W: A small fan of stars 1° from Ruchbah.
When it rises and sets tonight, how high it climbs and how much the Moon gets in the way are worked out in your browser for your place.
What you will see
- EyesNot visible to the naked eye.
- Binoculars (10×50)A small knot of stars, partly resolved.
- Telescope (6–8 inch)A group of faint stars.
For a dark country sky with no Moon. From a city, faint galaxies and nebulae can disappear completely.
Facts
| Designations | M103, NGC 581 |
|---|---|
| Type | Open cluster |
| Magnitude | 7.4The smaller the number, the brighter. |
| Apparent size | 6′the full Moon is 31′ across |
| Constellation | Cassiopeia |
| Right ascension (J2000) | 01h 33m 21.8s |
| Declination (J2000) | +60° 39′ 29″ |
More in Cassiopeia
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Sources and credits
Catalog data: OpenNGC by Mattia Verga, CC BY-SA 4.0, and d3-celestial by Olaf Frohn, BSD 3-Clause. All data sources →