Galaxy in Ursa Major
Cigar Galaxy (M82)
M81 came too close a few hundred million years ago, and this is the result: star formation running ten times too fast and a wind of gas blowing out of both faces of the galaxy. Those plumes are visible in amateur telescopes, which is unusual for anything this violent.
The wind is leaving at something like a thousand kilometres a second, carrying the galaxy's own gas out of reach, and within a few dozen million years the burst will have used up or expelled everything it had. It also produced the brightest supernova in decades in 2014, found by a class of students at a London teaching observatory.
- Catalogue
- M82
- Type
- Galaxy
- Constellation
- Ursa Major
- Distance
- 12 million light-years
- Apparent magnitude
- 8.4
- Surface brightness
- 20.9 mag/□″
- Apparent size
- 9′ × 4′
- Right ascension
- 9h 56m
- Declination
- +69.68°
- Found by
- Johann Elert Bode, 1774
Small enough that its 8.4 magnitudes arrive concentrated rather than smeared: 20.9 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 | Challenge | Challenge | Challenge | Challenge |
| Bortle 8 18.1 mag/□″ | No | No | No | No | No |
| Bortle 9 17.8 mag/□″ | No | No | No | No | No |
At the eyepiece
The more arresting half of the pair — a long, narrow, visibly mottled streak with a dark notch cut across the middle. That irregularity is real structure rather than an artefact, which is unusual at this distance and is why M82 tends to be remembered while M81 is admired.
When, and from where
Highest in the middle of the night in February. Circumpolar from most of Europe, Canada and the northern United States — it never sets there at all. From south of 20°S it never rises.
| Latitude | Highest it gets | |
|---|---|---|
| 60°N Oslo, Anchorage | 80° | Never sets |
| 51°N London, Calgary | 71° | Never sets |
| 40°N New York, Madrid | 60° | Never sets |
| 30°N Cairo, Houston | 50° | Never sets |
| 0°N the equator | 20° | |
| 33°S Sydney, Cape Town | — | Never rises |
Nearby in the sky
The whole catalogue →One more of the catalogue sits within five degrees, close enough to take in on the same night without moving far. Everything below is measured from M82 itself, not from the middle of Ursa Major.
- M81 Bode's Galaxy 37′ apart Ursa Major · magnitude 6.9 · binoculars from Bortle 5 or darker
- M108 Galaxy 16° apart Ursa Major · magnitude 10.0 · binoculars from Bortle 4 or darker
- M97 Owl Nebula 17° apart Ursa Major · magnitude 9.9 · binoculars from Bortle 4 or darker
- M40 Winnecke 4 19° apart Ursa Major · magnitude 8.4 · binoculars from Bortle 7 or darker
One of 110. Positions J2000; the sky is the final authority.