Galaxy in Ursa Major
M109
The most distant galaxy in the catalogue, and a barred spiral broadly like the one we live in. It lies half a degree from Phecda in the Plough, and that star's glare is the main thing standing between you and it. It anchors a group of some fifty galaxies and is the largest of them.
At eighty-four million light-years, the light arriving from it left before the Alps existed — which is worth remembering when the eyepiece shows a faint grey ellipse and nothing else, because that is what eighty-four million light-years looks like.
- Catalogue
- M109
- Type
- Galaxy
- Constellation
- Ursa Major
- Distance
- 84 million light-years
- Apparent magnitude
- 9.8
- Surface brightness
- 22.4 mag/□″
- Apparent size
- 8′ × 5′
- Right ascension
- 11h 58m
- Declination
- +53.38°
- Found by
- Pierre Méchain, 1781
Small enough that its 9.8 magnitudes arrive concentrated rather than smeared: 22.4 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 4.
| 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 | No | 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
The faintest galaxy on the list and made harder by Phecda sitting half a degree away, throwing light across the field. Move the star outside the eyepiece before you go looking. What you get is a small dim oval, and the bar is beyond ordinary reach.
When, and from where
Highest in the middle of the night in March. Well placed for the northern hemisphere and overhead for anyone near 53°N. South of 37°S it stays below the horizon.
| Latitude | Highest it gets | |
|---|---|---|
| 60°N Oslo, Anchorage | 83° | Never sets |
| 51°N London, Calgary | 88° | Never sets |
| 40°N New York, Madrid | 77° | Never sets |
| 30°N Cairo, Houston | 67° | |
| 0°N the equator | 37° | |
| 33°S Sydney, Cape Town | 4° | Low — in the murk |
Nearby in the sky
The whole catalogue →Nothing else in the catalogue is especially close; the nearest is 5.8° apart, which is a separate trip rather than a nudge of the tube. Everything below is measured from M109 itself, not from the middle of Ursa Major.
- M40 Winnecke 4 5.8° apart Ursa Major · magnitude 8.4 · binoculars from Bortle 7 or darker
- M97 Owl Nebula 6.5° apart Ursa Major · magnitude 9.9 · binoculars from Bortle 4 or darker
- M106 Galaxy 7.0° apart Canes Venatici · magnitude 8.4 · binoculars from Bortle 4 or darker
- M108 Galaxy 7.1° apart Ursa Major · magnitude 10.0 · binoculars from Bortle 4 or darker
One of 110. Positions J2000; the sky is the final authority.