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RA: 05h 34m 31.97s
Dec: +22° 00′ 52.1″
Ch: MSA:158, U2:135, SA:5
Ref: SIMBAD, Green (2001)
Type: supernova remnant, F
Mag: B=?, V=?
Size: 7′ x 5′
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NGC 1952 = M 1 = The Crab Nebula. This is the prototypical supernova remnant (from SN 1054), and is now a large, bright nebula. I have adopted the position of the pulsar near its center as the nebula's position as well. The pulsar, by the way, is the southern of the two stars of similar brightness near the nebula's center.
There is evidence, however, that in this case at least, the star has a large proper motion -- it is no longer at the center of the nebulosity implied by the measured expansion of the knots and filaments, but is several arcsec to the northwest. This is taken as evidence for an asymmetric supernova explosion which gave the star a powerful kick and set it off at high velocity.
In spite of all this, I'm sticking with the position of the pulsar as the center of the nebula for the time being. Perhaps I'll change my mind in a few thousand years when the star is well away from the center of the expanding gas cloud that Messier placed first in his famous list.
In the Philosophical Transactions, 1818, William Herschel wrote: "1783, 1794, 7 feet telescope. With 287 power, light without stars; 1805, 1809, 10 feet telescope. It is resolvable. There does not seem any milky nebulosity mixed with what I take to be small lucid points; 1805, large 10 feet telescope, with 220 the diameter is 4', with this power and light it is what must be called resolvable; 1809, with a fine new 10 feet, it is resolvable, and with 170 power some of the faint stars may be seen, it is however possible that faint milky nebulosity may be mixed with a few very small stars. As all the observations of the large telescopes agree to call this object resolvable, it is probably a cluster of stars at no very great distance beyond their gaging powers . . ."
Sketched and described.
The Earl of Rosse, observing with a 72-inch f/8.8 speculum telescope, recorded it 19 times.
Lassell, W. (1854) Observations of the nebula of Orion, made at Valletta, with the twenty-foot equatorial. Memoirs R.A.S., 23, 53-62.
Perhaps second unidentified object discussed on p.59?
Mentioned again p 61
"nebula, slightly condensed at centre; elliptical 3'x1'; the Crab Nebula."
Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.
Remarks, p.217: "The spectrum is gaseous."
Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part IV. M.N.R.A.S., 36(2), 58.
John herschel said it looked like "a heap of sand"
Ced 53 (NGC 1952)
Position (1900): RA 5 28.5, Dec + 21 57
Star: Anon (Mp=15.2)
Spectrum of nebula: emission spectrum (observed)
Classification: Neb associated with mainly one star (which may be multiple) - Quasi-planetary, representing a transitional type between real planetaries and bright diffuse nebulae (eg. NGC 1514)
Notes: "NGC 1952 = GC 1157 = h 357 = M 1 = "The Crab nebula". Disc. Bevis 1731. The object occurs in Bevis' atlas. WP 27. (27, 30, 103, 114, 174, 191, 216, 220, 232, 236, 242, 259, 300, 301, 354, 366, 454, 455, 457, 486, 489, 491, 500, 509, 578, 601, 603 Pl 14, 606, 615 Pl 26, 630 Pl 30, 631, 632, 641, 761, 791). R. Has also been classified as a planetary."
Lynds, B.T. (1962) Catalogue of dark nebulae. Astrophys.J.Suppl.Ser. 7, 1-52. [also: computer datafile: VII/7A]
The RNGC (Sulentic and Tifft 1973) notes that this is a planetary nebula.
See also "Visual Astronomy of the Deep Sky" by Roger N. Clark (1990, Sky Publishing Corporation) page 95.
"An optical atlas of galactic supernova remnants" [1973ApJS...26...19V]
Le Forbes (Stoke, St. Mary Bourne, Hampshire) observing from Puimichel, France, writes in The Webb Society Nebulae and Clusters Section Report No. 11, January 1993: "Very bright and dense with UHC filter increasing detail tremendously. The filaments shown in photographs are seen, and also the stars involved in / superimposed on the nebulosity. Vague hints of colour. (42-inch, x185/x310)"
Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "8.4M; 6'x 4' extent; the "CRAB" supernova remnant; neither N-filter nor P-filter help very much (???); detail visible at higher-x includes softer section to E; nebula is elongated with axis oriented N-S."
Houston writes: "Small telescopes reveal only a shapeless 8th mag blur variously sketched as oval, rectangular, or more often something inbetween. Increased magnification does not seem to change the appearance much."
John Bortle (Webb Society Quarterly Journal, January 1976) using 10x50 binoculars, estimates the visual magnitude as 8.8.
Rick Raasch writes in "The Focal Point", Volume 6, No. 3 (1993) "M1 The Crab Nebula is a supernova remnant and shows a flame-shaped nebulosity which is about 5' by 3' in extent. It is brighter in the center, an has ragged or fuzzy edges which suggest its name. This is the object which started Charles Messier logging non-cometary objects."
Donald J. Ware:"The Crab Nebula is a supernova remnant and shows a flame- shaped nebulosity which is about 5'by 3' in extent. It is brighter in the center, an has ragged or fuzzy edges which suggest its name. This is the object which started Charles Messier logging non-cometary objects."
05 34.5 +22 01
17.5: very bright, very large, 6'x4'. Very irregular elongated shape NW-SE with ragged edges. A dark indentation or bay intrudes on the NE side. A few faint stars are superimposed. Using an OIII filter, a bright inner streak is visible which is not noticeable without the filter.
13: large, bright, irregular potato shape, large indentation on NE side.
8: moderately bright, irregular, fairly large, indentation on NE and SE ends.
Observer: Adam Albino; Your skill: Intermediate; Date and UT: LMT: 97/12/20 08:45pm (UTC: 1997/12/21 00:45); Location & latitude: Norwell, MA - 25 miles S of Boston, MA; Site classification: Suburban; Limiting magnitude: 6; Seeing (1 to 10 - worst-best): 6-7; Moon up (phase?): No; Weather: Clear; Instrument: Celestron Ultima 8" PEC SCT / 80mm f-10 MAK Guide scope / 50mm Finder; Magnifications: 39X, 69X, 125X, 250X; Filters used: none; Object: M1 (Crab Nebula); Type: Supernova Remnant Mag. - 8.4; Constellation: Taurus; RA/DE: 5:34.5 / +22.01=92=20; Description:
A large soft elongated glow at 39X that is an easy Messier in the 8". Not viewable in my 50mm. At 69X a hint of an "S" shape becomes apparent, and at 125X and above, very easy. A small 13.5 mag star(s) is visible with an averted view near the center. The actual pulsar, of course, was not visible (16 mag?) At 125 and 250X some texture (unevenness) is noticeable which I take as filaments that are better seen in photos. In the 80mm, the "s" shape was seen at 125x although not clearly defined. No stars or "texture" seen at this aperture. I wonder at what aperture the central pulsar, and filaments would really be seen.
[amastro] posting, Sat Nov 25, 2006
82" telescope, McDonald Observatory near Fort Davis, Texas, USA
f/13.7, 35mm Televue Panoptic (5' fov, 812x)
The Crab Nebula was both spectacular and a little disappointing at the same time. It was a little bigger than the 5 arc-minute FOV and very bright, but I didn't see any of the detail that shows up in photos, there was none of the spider web detail that I expected to see. The central pair of stars were quite obvious, one of which is the pulsar, but I don't know which was which. It really was a nice object, spider web or not.
Location: Paardeberg (ASSA Cape Centre dark sky site) [33:34.4S, 18:51.3E]
Time: 20:55 SAST
Binocs: 15x70 Celestron
Readily seen as a faint, irregularly round glow, evenly illuminated. Diameter about 4.3'.
With zeta Tau in the field, one degree away. Zeta is one point of a keystone (with HD 36879, 37013 & 37439). The two westernmost stars (36879 & 37013) make an isoceles triangle with NGC 1952. A 9.2V star (HD 245198) lies 10.4' NW of HD 37013, vaguely in the direction of NGC 1952. The nebula's diameter is < 1/2 this separation but > 1/3.
In a two-inch refractor the nebula is just a featureless diffuse patch.
12-inch f5 (EP: 26mm SW, 20mm UW, 7mm UW)
Conditions: The most clear sky possible. Dark moon and stars magnitude 6 and fainter are visible with the naked eye. Excellent clean sky, limited star flickering and brilliant objects. Limiting Magnitude: 6.2.
Fairly bright, well defined and slight oval with slight irregularities on the sides of this nebula. Moderately uniform low surface brightness.
Observing site: Little Tycho Observatory
[5h 34m 30s, 22° 1m 0s] Almost invisible in the 24, a bit better in the 18, and still visible in the 12.5.
Observing site: Little Tycho Observatory
[5h 34m 30s, 22° 1m 0s] The celebrated crab nebula is but a dim smudge from my backyard.
Observing site: Pinnacles overlook
[5h 34m 30s, 22° 1m 0s] The delicate filagree strands of expanding gas were seen for the first time with the larger aperture.
The Messier objects
The Bennett objects
The Caldwell list
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