Galaxy in Canes Venatici
M106
A spiral with two extra arms made of glowing gas rather than stars, blown out by the black hole at its centre. The water masers orbiting that black hole gave the most direct distance measurement ever made to another galaxy — no assumptions, just geometry.
The maser measurement is the reason this galaxy matters out of all proportion to how it looks. Water molecules orbiting the black hole emit at a precise frequency, their motion shifts it, and the geometry of the disc can be solved directly — giving a distance with no rung of the ladder beneath it, and therefore a check on every other rung.
- Catalogue
- M106
- Type
- Galaxy
- Constellation
- Canes Venatici
- Distance
- 24 million light-years
- Apparent magnitude
- 8.4
- Surface brightness
- 22.5 mag/□″
- Apparent size
- 19′ × 8′
- Right ascension
- 12h 19m
- Declination
- +47.30°
- Found by
- Pierre Méchain, 1781
Magnitude 8.4 sounds comfortable and is spread over 19′, which brings it down to 22.5 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 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 | 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
Large, bright and pleasingly elongated, with a strong core and hints of unevenness along its length at 250mm. One of the more satisfying spring galaxies, and much less crowded than the Virgo region, so it is easier to be sure what you are looking at.
When, and from where
Highest in the middle of the night in March. Well placed for the northern hemisphere and overhead for anyone near 47°N. South of 43°S it stays below the horizon.
| Latitude | Highest it gets | |
|---|---|---|
| 60°N Oslo, Anchorage | 77° | Never sets |
| 51°N London, Calgary | 86° | Never sets |
| 40°N New York, Madrid | 83° | |
| 30°N Cairo, Houston | 73° | |
| 0°N the equator | 43° | |
| 33°S Sydney, Cape Town | 10° | Low — in the murk |
Nearby in the sky
The whole catalogue →Nothing else in the catalogue is especially close; the nearest is 7.0° apart, which is a separate trip rather than a nudge of the tube. Everything below is measured from M106 itself, not from the middle of Canes Venatici.
- M109 Galaxy 7.0° apart Ursa Major · magnitude 9.8 · binoculars from Bortle 4 or darker
- M94 Cat's Eye Galaxy 8.4° apart Canes Venatici · magnitude 8.2 · binoculars from Bortle 5 or darker
- M40 Winnecke 4 11° apart Ursa Major · magnitude 8.4 · binoculars from Bortle 7 or darker
- M63 Sunflower Galaxy 11° apart Canes Venatici · magnitude 8.6 · binoculars from Bortle 5 or darker
One of 110. Positions J2000; the sky is the final authority.