Planetary nebula in Lyra
Ring Nebula (M57)
The object that saddled planetary nebulae with their wrong name: through early telescopes the little disc looked like a planet, and the label stuck for two centuries after anyone believed it. It is a dead star's blown-off atmosphere, and a ring only because we are looking down the axis of a barrel.
The ring is expanding at about a kilometre a second and is perhaps seven thousand years old, which for a star is no time at all — the whole visible phase of a planetary nebula lasts a few tens of thousands of years before the gas thins out and stops glowing. The white dwarf at the middle is magnitude 15 and a genuine test of a large telescope.
- Catalogue
- M57
- Type
- Planetary nebula
- Constellation
- Lyra
- Distance
- 2,300 light-years
- Apparent magnitude
- 8.8
- Surface brightness
- 17.8 mag/□″
- Apparent size
- 1.4′ × 1′
- Right ascension
- 18h 54m
- Declination
- +33.03°
- Found by
- Antoine Darquier de Pellepoix, 1779
Small enough that its 8.8 magnitudes arrive concentrated rather than smeared: 17.8 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 6; with a 200mm from Bortle 9.
| 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 | Easy | Easy | Easy | Easy |
| Bortle 7 18.6 mag/□″ | No | No | Easy | Easy | Easy |
| Bortle 8 18.1 mag/□″ | No | No | Easy | Easy | Easy |
| Bortle 9 17.8 mag/□″ | No | No | Easy | Easy | Easy |
At the eyepiece
Findable in 80mm as a tiny grey ellipse and genuinely ring-shaped by 150mm — the hole in the middle is real and obvious, which almost nothing else at this scale offers. It takes magnification well. The central star needs a very large aperture and a very good night, and most people never see it.
When, and from where
Highest in the middle of the night in July. Passes overhead at 33°N and rises from everywhere except the far south — below 57°S it never clears the horizon.
| Latitude | Highest it gets | |
|---|---|---|
| 60°N Oslo, Anchorage | 63° | Never sets |
| 51°N London, Calgary | 72° | |
| 40°N New York, Madrid | 83° | |
| 30°N Cairo, Houston | 87° | |
| 0°N the equator | 57° | |
| 33°S Sydney, Cape Town | 24° |
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 M57 itself, not from the middle of Lyra.
- M56 Globular cluster 5.7° apart Lyra · magnitude 8.3 · binoculars from Bortle 5 or darker
- M27 Dumbbell Nebula 18° apart Vulpecula · magnitude 7.4 · binoculars from Bortle 5 or darker
- M29 Open cluster 19° apart Cygnus · magnitude 6.6 · binoculars from Bortle 9 or darker
- M71 Globular cluster 20° apart Sagitta · magnitude 8.2 · binoculars from Bortle 5 or darker
Terms on this page
- White dwarf The exposed core a low-mass star leaves behind, Earth-sized and slowly cooling forever.
One of 110. Positions J2000; the sky is the final authority.