Galaxy in Coma Berenices
M85
The northernmost of the Virgo galaxies, and a lenticular — the disc of a spiral with the arms gone and the gas spent. Except that the stars at its centre are only a few billion years old and it carries the marks of a merger, so something disturbed it long after it should have settled down.
It is also the site of a peculiar transient in 2006 — a stellar explosion too faint for a supernova and too bright for a nova, which is now generally read as two stars merging. A galaxy that ought to be quiet, with a young core and an unexplained bang in it.
- Catalogue
- M85
- Type
- Galaxy
- Constellation
- Coma Berenices
- Distance
- 60 million light-years
- Apparent magnitude
- 9.1
- Surface brightness
- 21.6 mag/□″
- Apparent size
- 7′ × 5′
- Right ascension
- 12h 25m
- Declination
- +18.18°
- Found by
- Pierre Méchain, 1781
Small enough that its 9.1 magnitudes arrive concentrated rather than smeared: 21.6 per square arcsecond, which is why it stands out from the sky better than its brightness alone suggests. Why surface brightness is the number that matters.
Could you see it?
Straightforward with 10×50 binoculars from Bortle 5.
| 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 | Easy | Easy | Easy | Easy |
| Bortle 5 20.3 mag/□″ | No | Easy | Easy | Easy | Easy |
| Bortle 6 19.3 mag/□″ | No | Challenge | Challenge | Challenge | Challenge |
| 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
A bright, smooth, featureless oval with no structure at any aperture, sitting at the northern edge of the Virgo crowd. Worth finding chiefly to know where the cluster stops, and because the small spiral NGC 4394 sits close enough to share the field.
When, and from where
Highest in the middle of the night in March. Passes overhead at 18°N and rises from everywhere except the far south — below 72°S it never clears the horizon.
| Latitude | Highest it gets | |
|---|---|---|
| 60°N Oslo, Anchorage | 48° | |
| 51°N London, Calgary | 57° | |
| 40°N New York, Madrid | 68° | |
| 30°N Cairo, Houston | 78° | |
| 0°N the equator | 72° | |
| 33°S Sydney, Cape Town | 39° |
Nearby in the sky
The whole catalogue →This is a busy patch. 4 more of the catalogue sit within five degrees, which is a binocular field or two — worth planning a session around rather than visiting once. Everything below is measured from M85 itself, not from the middle of Coma Berenices.
- M100 Galaxy 2.4° apart Coma Berenices · magnitude 9.3 · binoculars from Bortle 4 or darker
- M88 Galaxy 4.1° apart Coma Berenices · magnitude 9.6 · binoculars from Bortle 5 or darker
- M99 Galaxy 4.1° apart Coma Berenices · magnitude 9.9 · binoculars from Bortle 4 or darker
- M98 Galaxy 4.3° apart Coma Berenices · magnitude 10.1 · binoculars from Bortle 4 or darker
One of 110. Positions J2000; the sky is the final authority.