Home / Guides / Observing Crab Nebula (M1)
Observing Crab Nebula (M1)
The Crab Nebula is a supernova remnant and pulsar wind nebula in the constellation of Taurus. The common name comes from a drawing that somewhat resembled a crab with arms produced by William Parsons, 3rd Earl of Rosse, in 1842 or 1843 using a 36-inch (91 cm) telescope.
What Crab Nebula is
The Crab Nebula is a supernova remnant and pulsar wind nebula in the constellation of Taurus. The common name comes from a drawing that somewhat resembled a crab with arms produced by William Parsons, 3rd Earl of Rosse, in 1842 or 1843 using a 36-inch (91 cm) telescope. The nebula was discovered by English astronomer John Bevis in 1731. It corresponds with a bright supernova observed in AD 1054 by Mayan, Japanese, and Arab stargazers; this supernova was also recorded by Chinese astronomers as a guest star. The nebula was the first astronomical object identified that corresponds with a historically-observed supernova explosion.
How to observe it
This is a fainter target that rewards aperture and dark skies. A 150 mm or larger telescope from a site away from town lights shows it best, and averted vision helps.
Magnification is your telescope's focal length divided by your eyepiece's focal length. For an extended object like this, start low to frame it, then step up in power only if the object takes it. Use the Fit My Telescope tool to see the exact magnification, true field and exit pupil each of your eyepieces gives.
How it looks at the eyepiece
What you see at the eyepiece is fainter and less colourful than a photograph, because the eye takes in light in an instant while a camera builds it up over minutes. Expect a grey glow rather than the vivid colours of an image, and let your eyes dark-adapt for at least twenty minutes to see the most.
This object is the Crab Nebula, the remnant of a supernova recorded in 1054, which makes it a rewarding target once you have found it.
Frame it at low to medium power first with a wide true field, then step up the magnification only if the object stays sharp and the sky is steady. The Fit My Telescope tool shows the magnification, true field of view and exit pupil each of your eyepieces gives in your telescope, so you can pick the one that frames the object best.
The object in NASA imagery
NASA has imaged this object. One example in the NASA Image and Video Library is titled Most Detailed Image of the Crab Nebula, from JPL.
The Crab Nebula is one of the most intricately structured and highly dynamical objects ever observed. The new Hubble image of the Crab was assembled from 24 individual exposures taken with the NASA/ESA Hubble Space Telescope
NASA imagery is in the public domain. What you see through an eyepiece is fainter and mostly grey, since the eye does not accumulate light the way a long-exposure camera does, but knowing an object's true shape helps you recognise it at the telescope.
| Property | Value |
|---|---|
| Apparent magnitude | 8.4 |
| Catalogue | Messier 1 (M1) |
Object data from Wikidata (CC0) and standard Messier catalogues.
What magnification suits M1?
Open the Fit My Telescope toolSee the true field and exit pupil each eyepiece givesFind telescope eyepiece on eBayaffiliateRelated
Sources: Crab Nebula (Wikipedia, CC BY-SA) · Wikidata (CC0) · NASA Image and Video Library: PIA03606 (public domain)