Supernova remnant in Taurus
Crab Nebula (M1)
The wreckage of a star that Chinese astronomers watched explode in July 1054, bright enough to be visible in daylight for three weeks. It is still expanding, fast enough that photographs forty years apart show the difference.
At its centre is what is left of the star itself: a neutron star the size of a city, turning thirty times a second, and it is the rotation that keeps the whole nebula lit. Wind the expansion backwards and the debris converges on a date rather later than 1054, which means it has been speeding up.
- Catalogue
- M1
- Type
- Supernova remnant
- Constellation
- Taurus
- Distance
- 6,500 light-years
- Apparent magnitude
- 8.4
- Surface brightness
- 20.5 mag/□″
- Apparent size
- 6′ × 4′
- Right ascension
- 5h 35m
- Declination
- +22.02°
- Found by
- John Bevis, 1731
Small enough that its 8.4 magnitudes arrive concentrated rather than smeared: 20.5 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 | 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
Do not expect the photographs. In anything under 200mm it is a small grey oval with no detail whatsoever, and the filaments that make it famous need a large aperture and a nebula filter before they resolve into anything. It is worth finding anyway, for what it is rather than what it looks like.
When, and from where
Highest in the middle of the night in December. Passes overhead at 22°N and rises from everywhere except the far south — below 68°S it never clears the horizon.
| Latitude | Highest it gets | |
|---|---|---|
| 60°N Oslo, Anchorage | 52° | |
| 51°N London, Calgary | 61° | |
| 40°N New York, Madrid | 72° | |
| 30°N Cairo, Houston | 82° | |
| 0°N the equator | 68° | |
| 33°S Sydney, Cape Town | 35° |
Nearby in the sky
The whole catalogue →Nothing else in the catalogue is especially close; the nearest is 8.2° apart, which is a separate trip rather than a nudge of the tube. Everything below is measured from M1 itself, not from the middle of Taurus.
- M35 Open cluster 8.2° apart Gemini · magnitude 5.3 · binoculars from Bortle 9 or darker
- M37 Open cluster 11° apart Auriga · magnitude 6.2 · binoculars from Bortle 9 or darker
- M36 Open cluster 12° apart Auriga · magnitude 6.3 · binoculars from Bortle 9 or darker
- M38 Open cluster 14° apart Auriga · magnitude 7.4 · binoculars from Bortle 9 or darker
Terms on this page
- Neutron star A city-sized remnant so dense that a sugar cube of it would weigh as much as a mountain.
One of 110. Positions J2000; the sky is the final authority.