Galaxy in Ursa Major
Bode's Galaxy (M81)
A near-perfect grand-design spiral and one of the brightest galaxies in the sky. A few observers with exceptional eyes under exceptional skies have claimed it without a telescope — twelve million light-years, which if any of them are right is the furthest a human being has ever seen unaided.
It anchors the nearest large group of galaxies outside our own, and a bridge of hydrogen runs from it to M82 and NGC 3077 — the material pulled loose during the encounter that wrecked its neighbour. In the eyepiece the arms are hard and the core is easy, which is the usual bargain with any spiral this far away.
- Catalogue
- M81
- Type
- Galaxy
- Constellation
- Ursa Major
- Distance
- 12 million light-years
- Apparent magnitude
- 6.9
- Surface brightness
- 21.3 mag/□″
- Apparent size
- 21′ × 10′
- Right ascension
- 9h 56m
- Declination
- +69.07°
- Found by
- Johann Elert Bode, 1774
Magnitude 6.9 sounds comfortable and is spread over 21′, which brings it down to 21.3 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 the naked eye from Bortle 2 or darker; with 10×50 binoculars from Bortle 5.
| Sky | Eye | 10×50 | 80mm | 130mm | 200mm |
|---|---|---|---|---|---|
| Bortle 1 21.9 mag/□″ | Easy | Easy | Easy | Easy | Easy |
| Bortle 2 21.7 mag/□″ | Easy | 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 best pair on this list with M82: both in one low-power field, one a smooth bright oval and the other a torn streak. M81 shows its core strongly and its arms grudgingly, and 200mm from a dark site is where they start to appear.
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 21°S it never rises.
| Latitude | Highest it gets | |
|---|---|---|
| 60°N Oslo, Anchorage | 81° | Never sets |
| 51°N London, Calgary | 72° | Never sets |
| 40°N New York, Madrid | 61° | Never sets |
| 30°N Cairo, Houston | 51° | Never sets |
| 0°N the equator | 21° | |
| 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 M81 itself, not from the middle of Ursa Major.
- M82 Cigar Galaxy 37′ apart Ursa Major · magnitude 8.4 · 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.