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Al di la della Luna; Beyond the Moon; Astrophotography; Astrofotografia; Danilo Pivato
 
 
 
 
 
 
 
The Analysis of Frame
 
M 1 - Supernova Remnant: in Taurus - NGC 1952; Crab Nebula; Taurus A; 3C 144; LBN 833; Sh2-244; h 357; GN 05.31.5; GC 1157; LBN 184.62-05.65; Mills 05+2A; SNR G184.6-05.8; PKS 0531+21.0 - [field: 1,4° x 2,1°] - - - Mag. Limite: 18.5^ - 19.0^ (r) - Fonte: USNO A1 - Object Coordinates: RAJ2000.0 05h 34m 31.94s - Dec J2000.0 +22° 00' 52.2" [SIMBAD] - Magnitudine: 8.4^ (b); --.-^ (v), --,-^ (r); ; Surface Brightness: --.-^ - Object Size: 7,0' x 5,0' [SIMBAD] - Position Angle: ---° - Object Classification: 2;3:3 Redshift z(~) V (Km/s): --- - Spectrum: --- Questo famoso residuo di supernova è il primo oggetto del catalogo di Messier pubblicato da Charles Messier nel 1774. La storia della sua scoperta è alquanto articolata. Alcune cronache riportano che la sera del 28 agosto del 1758 [curiosità del sottoscritto: questa data anticipa esattamente di due secoli la mia nascita (!)], Messier cercava di puntare con il suo telescopio preferito la cometa che egli stesso aveva scoperto un paio di settimane prima. Stava osservando dalla sua postazione all'Hotel de Cluny, a Parigi, quando nel campo dell'oculare gli apparve, per puro caso, un oggetto insolito, strano, che descrive in questo modo: "...Quando la cometa del 1758 si trovava fra le corna del Toro, scoprii nei pressi del corno meridionale, ad una breve distanza dalla stella z, Tauri, una pallida luce biancastra, a guisa dei una fiammella di candela e priva di stelle nel suo interno. Questa luce somigliava a quella della cometa da me osservata, sebbene mi sembrasse troppo lucente, biancastra e allungata per essere una cometa, le quali prima di allora. mi erano sempre apparse rotondeggianti..." Dopo aver scritto questo appunto Messier ne annotò con cura la posizione. Questa nebulosa possiede una lunga serie di sigle e nomi alternativi, quelli sopra riportati ne sono una minima parte, ma da molti viene identificata come Crab Nebula o Nebulosa Granchio. Tale nome le venne attribuito per la prima volta da William Parsons terzo Conte di Rosse attorno alla metà del 1800. Lord Rosse infatti la osservò con il suo Leviatano (1,80m di diametro), rilevando oltre al colore biancastro ed alla sua forma nettamente allungata, anche un certo numero di filamenti irregolari. che gli suggerirono il nome. Si può ragionevolmente affermare che la Crab Nebula sia stato e lo è tutt'ora, uno degli oggetti del cielo più studiati del secolo passato. Le prime curiosità di carattere scientifico risalgono al 1921, quando l'astronomo Knut Emil Lundmark si rese conto che l'oggetto, ripreso a distanza di anni in due fotografie diverse, appariva dotato di un moto di espansione; le sue dimensioni apparenti erano variate di una quantità non trascurabile. Lo stesso Lundmark notò che tale oggetto aveva proprio la posizione occupata dalla "supernova" descritta nelle cronache cinesi e arabe risalenti al 1054. Oggi sappiamo che questi gas si espandono alla velocità 1500 Km/s. Nella fotografia in luminanza qui sopra riprodotta la Crab Nebula appare piccolina e alla distanza apparente di 1° 08' dalla stella più brillante che ne facilità l'identificazione: z Tau. Da questa stessa scala-immagine in M1 si iniziano ad identificare i filamenti irregolari, ricordandoci probabilmente come deve averla vista Lord Rosse nel 1758 con il suo gigantesco telescopio. Curioso come tutta l'area intorno alla Crab Nebula sia quasi del tutto priva di oggetti Deep-Sky appariscenti! Poche galassie, 5 stelle variabili e null'altro.(...continua)
 
 
 
Stelle variabili:
 
V* Zet Tau - Be Star - 123 Tau; SAO 77336; BD+21 908; CEL 864; 2E 1440; FK5 211; GCRV 3468; AAVSO 0531+21; PPM 94584; HIP 26451; - E' la stella del corno sud del Toro ed è una stella binaria la cui componente principale è una gigante blu di tipo spettrale B2IIIpe, anche se i vari studi non concordano perfettamente fra loro è stata spesso classificata anche di classe B4. E' anche una variabile di tipo Gamma Cassiopeiae; con un'età di circa 25 milioni di anni sta giungendo al termine, o ha già concluso, il ciclo di fusione dell'idrogeno in elio.
 
V* 1259 - Variable star of Mira Cet type - NSV 2442; CSV 629; HV 6914; NSVS J0537267+222031; Prag 2765 - Object Coordinates: RAJ2000.0 05h 37m 26.66s - Dec J2000.0 +22° 20' 31.2" [AAVSO] - Magnitudine range: 15.0^-18.0 (B); --.-^ (v), --,-^ (r); ; Surface Brightness: --.-^ - Object Size: -,-' x -,-' [---] - Position Angle: ---° - Object Classification: --- Redshift z(~) V (Km/s): --- - Spectral type: A2
 
V* HD 245010 - NSV 2192; BD+21 894; CSV 100527; GSC 01309-01519; Zinn 0392; GSC 01309-01519 - Object Coordinates: RAJ2000.0 05h 34m 54.55s - Dec J2000.0 +21° 56' 44.8" [AAVSO] - Magnitudine range: 10.2^ (v); --.-^ (b), --,-^ (r); ; Surface Brightness: --.-^ - Object Size: -,-' x -,-' [---] - Position Angle: ---° - Object Classification: --- Redshift z(~) V (Km/s): --- - Spectral type: A2 --- Period: 230 d
 
 
 
History of Observation and description:
 
Discovered 1731 by British amateur astronomer John Bevis.
 

The Supernova was noted on July 4, 1054 A.D. by Chinese astronomers as a new or "guest star," and was about four times brighter than Venus, or about mag -6. According to the records, it was visible in daylight for 23 days, and 653 days to the naked eye in the night sky. It was probably also recorded by Anasazi Indian artists (in present-day Arizona and New Mexico), as findings in Navaho Canyon and White Mesa (both Arizona) as well as in the Chaco Canyon National Park (New Mexico) indicate; there's a review of the research on the Chaco Canyon Anasazi art online. In addition, Ralph R. Robbins of the University of Texas has found Mimbres Indian art from New Mexico, possibly depicting the supernova.

The Supernova 1054 was also assigned the variable star designation CM Tauri. It is one of few historically observed supernovae in our Milky Way Galaxy.

 
Charles Messier: 1758 September 12. 1. 5h 20m 02s (80d 00' 33") +21d 45' 27"
Nebula above the southern horn of Taurus, it doesn't contain any star; it is a whitish light, elongated in the shape of a flame of a candle, discovered while observing the comet of 1758. See the chart of that comet, Mem. Acad. of the year 1759, page 188; observed by Dr. Bevis in about 1731. It is reported on the English Celestial Atlas.

[A note in Messier's handwriting added in the margin of his copy of the Connoissance des Temps for 1783 reads:]
This nebula reported on the great English atlas: Seen by Dr Bevis about 1731. according to his letter written to me on 10th June 1771.

[In the Mem. Acad. for 1959, the discovery announce for this nebula is described in the memoir by Delisle on the comet of 1758, Comet De la Nux: Report of M1's discovery by Messier, from: Joseph Nicholas Delisle, 1759. Mémoire sur la comète de 1758 (Memoir on the comet of 1758). Mém. Acad. 1759, p. 154-188]

[p. 165. Discovery of a new nebula.] [On August 28, 1758,] M. Messier discovered there a light almost resembling that of the Comet, but which was even more vivid, whiter & a bit more elongated than the Comet he observed at that time: That comet had appeared to him always almost round in its coma, without an appearance of either a tail or a beard. When the discovery of this new light or nebulous star didn't come to an end of the observations of that morning session, before the sky covered, M. Messier didn't have the time to determine its exact situation with respect to the neighboring stars of the southern horn of Taurus: there will be reported the details of observations, & there will be marked the precise position of that new nebula, its magnitude & the degree of its light compared to that of the Comet of 1758, [..]
[p. 169] [Messier] also has determined exactly on [September] 10 in the morning the position of the nebula, which he had commenced to perceive on August 28 in the morning near the southern horn of Taurus.
[p. 170. Difference of the appearances of the Comet & the new nebula.] [The night of September 11 to 12] .. having compared the appearance or the light of the Comet with that of the nebula of the southern horn of Taurus, one finds there well a difference, the light of the nebula was considerably stronger in this morning than that of the Comet; instead of, like the two preceding days, when the two lights were approaching equality to each other, that of the Comet was always fainter [..]

 

Johan Elert Bode: A nebula without stars.
On November 8 [1774], I looked up the nebula which Mr. Messier has discovered in 1758 according to the French memoirs, situated obliquely north above Zeta at the southern horn of Taurus. I found this object soon with the 7-foot telescope, and in the position listed by Mr. Messier relative to the stars situated closest to it, as the 8th figure shows.

Taurus 292 [From: Vorstellung der Gestirne auf XXXIV Kupfertafeln (Introduction to the Stars on 34 Copper Plates), 1782. Here p. 18, plate 14]
Taurus 292, after Messier. RA = 80:20 [05:21.3], Dec = +21:47. Nebulous patch.

 
Frederick William Herschel: [1784. PT Vol. LXXIV=74 (1784), p. 437-451, here p. 440]
".. To these may added the 1st [M1], 3d, 27, 33, 57, 79, 81, 82, 101 [of Messier's catalog], which in my 7, 10, and 20-feet reflectors shewed a mottled kind of nebulosity, which I shall call resolvable; so that I expect my present telescope will, perhaps, render the stars visible of which I suppose them to be composed. .."

[1814. PT 1814 (vol. 104), p. 248-284, here p. 260]
8. Of objects of ambiguous construction
".. But when an object is of such a construction, or at such a distance from us, that the highest power of penetration, which hitherto has been applied to it, leaves it undetermined whether it belongs to the class of nebulae or of stars, it may be called ambiguous. As there is, however, a considerable difference in the ambiguity of such objects, I have arranged 71 of them into the following four collections. [First collection contains M1]
The first contains seven objects that may be supposed to consist of stars, but where the observations hitherto made, of either their appearance or form, leave it undecided into which class they should be placed.
..
The objects in this collection must at present remain ambiguous."

[1818. PT 1818 (vol. 108), 429-470, here p. 345. Reprinted in: Scientific papers, Vol. II, p. 595]
Observations of the 1st of the connoissance des temps.
"1783, 1794, 7 feet [FL] telescope. With 287 [magnification], light without stars."
"1805, 1809, 10 feet telescope. It is resolvable [mottled]. There does not seem any milky nebulosity miced with what I take to be small lucid points."
"1783, 1784, 1809, 20 feet telescope. Very bright, of an irregular figure; full 5 minutes in longest direction. I suspect it to consist of stars."
"1805, large 10 feet telescope. With 220 the diameter is 4'0"; with this power and light it is what must be called resolvable [mottled]."
As all the observations of the large telescopes agree to call this object resolvable, it is properly a cluster of stars at no very great distance beyond their gaging powers; its profundity may therefore be of about the 980th order. It is near the milky way.

 
John Frederick William Herschel: h 357 = M1.
Sweep 59 (February 24, 1827).
RA 5h 24m 15.7s, NPD 68d 6' 36" (1830.0) [Right Ascension and North Polar Distance]
vL; E; vglbM; r; 4'l, 3'br; pos of longer axis n p to s f. A fine object. See fig. 81.
Very large; extended; very gradually brightening a little toward the middle; mottled; 4' long, 3' broad; position angle of longer axis north preceding to south following. A fine object. See figure 81.

Plate XVI, Fig. 81. [p. 503]
Fig. 81, .. are clusters of stars, beginning with a barely resolved one, (M. 1. fig. 81,) and ascending by successive degrees, ..

 
William Henry Smyth: CCXII [212]. M1.CCXII. 1 M. Tauri.
AR 5h 24m 51s, Dec N 21d 54'.2
Mean Epoch of Observation: 1836.99 [Dec 1836]
[with drawing]
A large nebula, pearly white, about a degree north-west of the star Zeta on the tip of the Bull's southern horn, and on the outskirts of the galaxy. It is of an oval form, with its axis-major trending np to sf, and the brightest portion toward the south. Sir John Herschel registers this in his Catalogue of 1833, as a "barely resolvable cluster;" and figures it with a fair elliptical boundary. He applied his 7, 10, and 20-foot reflectors, and endeavoured to ascertain its relative distance by a modification of their space-penetrating capacities. "As all the observations," he concluded, "of the large telescopes agree to call this object resolvable, it is probably a cluster of stars at no very great distance beyond their gauging powers; its profundity may therefore be of about the 980th order." All this shows the difficulty of what, to my view, is rather a milky nebulosity than a cluster. Thhe powerful telescope constructed by Lord Rosse, however, not only displays the component stars distinctly, but also shows several fringy appendages around, and a deep bifurcation to the south. So do siderial wonders increase with our means of optical practice!
This fine nebula is remarkable as having been discovered by M. Messier - the comet-ferret of Louis XV. - while observing Zeta Tauri and a comet in 1758, when he cought up a "a whitish light, elongated like the flame of a taper." This accident induced him to form his wellknown and useful Catalogue of nebulae and clusters, from the observations of himself, La Caille, and Méchain, in order to prevent astronomers from mistaking any of those for comets; and the List of 103 which he furnished to the public, was considered to have scraped them all together, as far as climate permitted. Whence D'Alembert, speaking of Messier, observed, "on ne peut s'empêcher de regretter qu'un Observateur si exact et si plein de zèle, n'ait pat été placé dans un climate plus heureux." But the progress of astronomy has not depended on climate, as the names Tycho, Römer, Flamsteed, Bradley, Hevelius, Huygens, Schroeter, Olbers, and others of the Iera Phalanx [written in Greek], abundantly testify. Indeed, in the department before us, within twenty years of Messier's publication, the illustrious Sir William Herschel increased the 103 by 2500 new members, in the decried climate of England, thus affording a strong instance how moral causes can control the physical. Piazzi, whose observatory in the Conca d'Oro was to the eye most charmingly situated, was so troubled with a peculiar flickery hot aerial refraction, that one night he exclaimed to me, "Ah, Greenwich is the paradise for an observer!"
It is rather curious, on recollecting that this nebula was the first caught up in seeking the comet of 1759, that it was also a mare's nest to more than one astronomical tyro in August, 1835, when on the look-out for the return of Halley's comet, in the very month in which it had first been seen seventy-five years before: and Zeta Tauri was also the star which served as "pointer", on that interesting advent.
 
William Parsons, 3rd Earl of Rosse - Lord Rosse: [Phil. Trans. 1844, p. 321-324, drawing on plate XVIII, Fig. 81; on his observation with his 3-feet (36-inch) aperture telescope]
"Fig. 81 is also a cluster; we perceive in this [36-inch telescope], however, a considerable change of appearance; it is no longer an oval resolvable [mottled] Nebula; we see resolvable filaments singularly disposed, springing principally from its southern extremity, and not, as is usual in clusters, irregularly in all directions. Probably greater power would bring out other filaments, and it would then assume the ordinary form of a cluster. It is stubbed with stars, mixed however with a nebulosity probably consisting of stars too minute to be recognized. It is an easy object, and I have shown it to many, and all have been at once struck with its remarkable aspect. Everything in the sketch can be seen under moderately favourable circumstances."
 
Thomas William Webb: Oblong; pale; 1 deg np [North Preceding, NW of] Zeta [Tauri].
Espin: Winlock, gaseous spectrum.
 
John Herschel, General Catalogue: GC 1157 - GC 1157 = h 357 = M1.
RA 05h 26m 3.9s, NPD 68d 5' 10.5" (1860.0) [Right Ascension and North Polar Distance]
vB; vL; E135deg +/-; vglbM, r. 12 observations by W. & J. Herschel.
Very bright, very large, extended along position angle approximately 135 deg; very gradually brightening a little toward the middle, mottled.
Remark: Figures in P.T. 33 [JH 1833], plate viii, Fig. 81; P.T. 44 [Lord Rosse, 1844], plate xix, Fig. 81; R. di. (The woodcut diagrams in Lord Rosse's paper, PT 1861); d'Arr. (D'Arrest's Inaugural dissertation and description of the Copenhagen Equatorial, 1861), plate ii, Fig. 4; Lass. (Lassell's Memoirs in vol xxiii of the Transactions of the Royal Astronomical Society), plate ii, Fig. 1.
 
Padre Pietro Angelo Secchi: [Descrizione del nuovo osservatorio del Collegio Romano, 1856]
[Drawing on Plate IV, Fig. 8]
 
William Lassell: [Memoirs of the Royal Astronomical Society, Vol. XXXVI (36)]
[Drawing on Plate II, Fig. 6]
 
John Louis Emil Dreyer: (1877) - GC 1157. The "Crab Nebula." No published drawing is satisfactory: The one in Phil. Trans. 1844 (Rosse 1844) is not at all like the object. The diagram in Phil. Trans. 1861 (Rosse 1861) gives a very fair general idea of its form, the dark lanes, &c.
 

John Louis Emil Dreyer: NGC 1952

NGC 1952 = GC 1157 = h 357; Bevis 1731, M 1.
RA 05h 26m 6s, NPD 68d 5.0' (1860.0) [Right Ascension and North Polar Distance]
vB, vL, E 135deg +/-, vglbM, r; = M1
Very bright, very large, extended along position angle approximately 135 deg; very gradually brightening a little toward the middle, mottled.
Remark: Figures in P.T. 33 [JH 1833], plate XVI, fig. 81; P.T. 44 [Lord Rosse, 1844], plate XIX, fig. 81; R. di. [The woodcut diagrams in Lord Rosse's paper, PT 1861); d'A. (D'Arrest's Inaugural dissertation and description of the Copenhagen Equatorial, 1861], plate II, fig. 4; Lass. [Lassell's Memoirs in vol xxiii of the Transactions of the Royal Astronomical Society], plate II, fig. 1; Secchi [Secchi, Memorie dell' Osserv. del Collegio Romano, 1852-55], plate IV, fig. 8; Lass. 2 [Lassell, Memoirs RAS, vol xxxvi], plate II, fig. 6; Ld R [Lord Rosse, Observations of Nebulae and Clusters at Birr Castle, 1848-78 (Transactions Royal Dublin Societym vol. ii, 1880)], plate II; Tempel [Ueber Nebelflecken (Abh. d. K. Böhm. Gesell. d. Wiss. 1885)], plate I.

 
John Ellard Gore: [The Observatory, Vol. 25, pp. 264-269, here pp. 264-265.]
Messier 1. R.A. 5h 28m.5, N. 21d 57'. - The famous "crab nebula" in Taurus. It lies about 1 degree north preceding the star Zeta Tauri. It was first seen by Bevis in 1731. It was again seen by Messier in 1758 while observing the comet of that year, and its rediscovery induced him to form his catalogue of nebulae, to help observers in distinguishing these objects from comets. Sir John Herschel thought it was a cluster of stars at a distance "of about the 980th order," that is 980 times the distance of Capella or Vega. Lord Rosse's telescope is said to have resolved it into stars, but photographs taken by Dr. Roberts in 1892 and 1896 show a very nebulous appearance, and with but little of the "crab-like" form depicted in Lord Rosse's drawing.
 
Camille Flammarion: [L'Astronomie. Revue de la Societé Astronomique de France, pp. 385-400 (November 1917), here pp. 396-397. With a photo and a drawing]
M.1. Taurus. Nebula with stars.
Messier's Description: "Nebula above the southern horn of Taurus, it doesn't contain any star; it is a whitish light, elongated in the shape of a flame of a candle, discovered while observing the comet of 1758."
Messier has added, in the margin, a writing which is still very readable: "This nebula is reported in the great english atlas. Seen by the doctor Bévis, in 1731, according to a letter to me from him, of June 10, 1771."
Seen on August 28, and the position determined on September 12 (1758).
It is on lurking on the return of the comet of Halley, of which we have talked more extensively, that Messier did this first discovery, near the star Zeta Tauri.
Observed by John Herschel, Admiral Smyth, d'Arrest, Lord Rosse, Schoenfeld, Lassell, Secchi, Dreyer, Webb, etc., it has received by Lord Rosse the name Crab Nebula. At most, it offers a little resemblance with the crabs which one finds at the shore of the English Channel, irregularly round, and much more like the elongated figure which I have published in Les Étoiles [The Stars], after Lord Rosse. The diverse drawings which have been made of it differ enormously.
This nebula has been photographed often enough at Juvisy since 1902. We have reobserved it in September and October 1917. The photograph reproduced here has been taken by M. Quénisset, on October 18 with a Voigtlender lens (exposed 1h 30m), and the drawing has been made by him on October 15.
Its shape is oval, almost quadrangular, measures 5' 1/2 in length and 3' 1/2 in width. Partly resolvable in more powerful instruments.
 
Heber Doust Curtis: [Descriptions of 762 Nebulae and Clusters photographed with the Crossley Reflector. Publ. Lick Obs., No. 13, Part I, p. 9-42]
NGC 1952, RA= 5:28.5, Dec=+21:57. The ``Crab'' Nebula in Taurus; [Publ. Lick Obs.] Vol. VIII, Plate 9. Planetary ? 0 s.n.

[The Planetary Nebulae. Publ. Lick Obs., No. 13, Part III, p. 55-74]
[with Lick b/w photo, Fig. 11]
NGC 1952; 5h 28.5m; +21d 57'
The ``Crab'' Nebula. Enlarged 5.2 times from a negative of 2h 30m exposure time. Two stars of magn. 16 are close together near the center, but it is not certain that either of them is a central star. This very complex and intricate object is nearly 6' long by 4' broad, in p.a. about 125 deg. It is not a typical planetary in form, and it is doubtful whether it is properly to be included as a member of the class. The nebular matter is intrinsically quite faint. Rel. Exp. 60.

 
 
 
 
 
 
 
 
 
       
 
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