Galaxy in Andromeda
M110
Messier drew this one in 1773 and then, for reasons nobody has established, left it off his list. An amateur astronomer named Kenneth Glyn Jones finally added it in 1966 — two centuries late, and almost certainly the last number the catalogue will ever be given.
It is a dwarf elliptical with dust lanes and some sign of recent star formation, both of which ellipticals are not supposed to have, and it is being slowly taken apart by Andromeda in the same way M32 was. Messier's omission was not carelessness — he drew it accurately — and no explanation for it has ever been found.
- Catalogue
- M110
- Type
- Galaxy
- Constellation
- Andromeda
- Distance
- 2.7 million light-years
- Apparent magnitude
- 8.5
- Surface brightness
- 22.7 mag/□″
- Apparent size
- 17′ × 10′
- Right ascension
- 0h 40m
- Declination
- +41.68°
- Found by
- Charles Messier, 1773
Magnitude 8.5 sounds comfortable and is spread over 17′, which brings it down to 22.7 per square arcsecond — the number that actually decides whether there is anything to see. Why surface brightness is the number that matters.
Could you see it?
Straightforward with 10×50 binoculars from Bortle 3.
| Sky | Eye | 10×50 | 80mm | 130mm | 200mm |
|---|---|---|---|---|---|
| Bortle 1 21.9 mag/□″ | No | Easy | Easy | Easy | Easy |
| Bortle 2 21.7 mag/□″ | No | Easy | Easy | Easy | Easy |
| Bortle 3 21.4 mag/□″ | No | Easy | Easy | Easy | Easy |
| Bortle 4 20.9 mag/□″ | No | Challenge | Challenge | Challenge | Challenge |
| Bortle 5 20.3 mag/□″ | No | Challenge | Challenge | Challenge | Challenge |
| Bortle 6 19.3 mag/□″ | No | No | No | No | No |
| Bortle 7 18.6 mag/□″ | No | No | No | No | No |
| Bortle 8 18.1 mag/□″ | No | No | No | No | No |
| Bortle 9 17.8 mag/□″ | No | No | No | No | No |
At the eyepiece
Larger and considerably fainter than M32 on the other side of Andromeda's core, and a genuine test of a suburban sky. An elongated, even glow with no detail. Getting all three — M31, M32 and M110 — in one field is the thing worth doing here.
When, and from where
Highest in the middle of the night in September. Well placed for the northern hemisphere and overhead for anyone near 42°N. South of 48°S it stays below the horizon.
| Latitude | Highest it gets | |
|---|---|---|
| 60°N Oslo, Anchorage | 72° | Never sets |
| 51°N London, Calgary | 81° | Never sets |
| 40°N New York, Madrid | 88° | |
| 30°N Cairo, Houston | 78° | |
| 0°N the equator | 48° | |
| 33°S Sydney, Cape Town | 15° | Low — in the murk |
Nearby in the sky
The whole catalogue →2 more of the catalogue sit within five degrees, close enough to take in on the same night without moving far. Everything below is measured from M110 itself, not from the middle of Andromeda.
- M31 Andromeda Galaxy 36′ apart Andromeda · magnitude 3.4 · binoculars from Bortle 4 or darker
- M32 Galaxy 55′ apart Andromeda · magnitude 8.1 · binoculars from Bortle 5 or darker
- M76 Little Dumbbell 14° apart Perseus · magnitude 10.1 · binoculars from Bortle 4 or darker
- M33 Triangulum Galaxy 15° apart Triangulum · magnitude 5.7 · binoculars from Bortle 3 or darker
One of 110. Positions J2000; the sky is the final authority.