Globular cluster in Lyra
M56
A small, unassuming globular halfway between Albireo and the Ring Nebula, both of which are more interesting. It is approaching us at 145 kilometres a second, which is fast even for a halo object.
It is also unusually poor in heavy elements even by globular standards, which along with that velocity and a retrograde-looking orbit has it down as an immigrant — the core of some small galaxy the Milky Way absorbed long enough ago that nothing else of it is left. A dull object with an interesting history is still a dull object at the eyepiece.
- Catalogue
- M56
- Type
- Globular cluster
- Constellation
- Lyra
- Distance
- 32,900 light-years
- Apparent magnitude
- 8.3
- Surface brightness
- 21.2 mag/□″
- Apparent size
- 7′
- Right ascension
- 19h 17m
- Declination
- +30.18°
- Found by
- Charles Messier, 1779
Small enough that its 8.3 magnitudes arrive concentrated rather than smeared: 21.2 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
Faint, small and unremarkable, resolving only at the edges with 200mm. Its redeeming feature is position: it costs nothing to stop here on the way between two far better things, and most people meet it exactly that way.
When, and from where
Highest in the middle of the night in July. Passes overhead at 30°N and rises from everywhere except the far south — below 60°S it never clears the horizon.
| Latitude | Highest it gets | |
|---|---|---|
| 60°N Oslo, Anchorage | 60° | Never sets |
| 51°N London, Calgary | 69° | |
| 40°N New York, Madrid | 80° | |
| 30°N Cairo, Houston | 90° | |
| 0°N the equator | 60° | |
| 33°S Sydney, Cape Town | 27° |
Nearby in the sky
The whole catalogue →Nothing else in the catalogue is especially close; the nearest is 5.7° apart, which is a separate trip rather than a nudge of the tube. Everything below is measured from M56 itself, not from the middle of Lyra.
- M57 Ring Nebula 5.7° apart Lyra · magnitude 8.8 · binoculars from Bortle 6 or darker
- M27 Dumbbell Nebula 12° apart Vulpecula · magnitude 7.4 · binoculars from Bortle 5 or darker
- M71 Globular cluster 14° apart Sagitta · magnitude 8.2 · binoculars from Bortle 5 or darker
- M29 Open cluster 16° apart Cygnus · magnitude 6.6 · binoculars from Bortle 9 or darker
One of 110. Positions J2000; the sky is the final authority.