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NGC 6 |
NGC 6/20 |
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Riga 1:
{{Oggetto non stellare
|nome = NGC 6 / NGC 20
|immagine = NGC 0006 2MASS.jpg
|image_text = NGC 6
Riga 7:
|epoca = J2000.0
|costellazione = Andromeda
|ra = {{RA|00|09|32,
| titolo=NGC 6
| opera= [http://nedwww.ipac.caltech.edu/ NASA/IPAC Extragalactic Database]
| url=http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=NGC+6
| accesso=17-02-2010
}}</ref>
|dec = {{DEC|+33|18|31}}<ref name="ned"/>
|dist_al = 210
|misura = milioni
|pre_dist_pc =
|dist_pc = 64,5
|misura_pc = Mpc
|note_dist_pc = <ref name="ned"/>
|appmag_v =
|dimensione_v = 1,
|luminosita_sup =
|redshift = 0,
| cognome = Falco | nome = Emilio E. | coautori = Kurtz, Michael J.; Geller, Margaret J.; Huchra, John P.; Peters, James; Berlind, Perry; Mink, Douglas J.; Tokarz, Susan P.; Elwell, Barbara | anno = 1999
| titolo = The Updated Zwicky Catalog (UZC)
| rivista = Publications of the Astronomical Society of the Pacific | volume = 111 | numero = 758 | pagine =438-452
| doi = 10.1086/316343 | url = http://adsabs.harvard.edu/abs/1999PASP..111..438F
| accesso = 18-02-2010
}}</ref>
|angolo_posizione = 140°<ref name="ugc">{{en}} {{cita web
| titolo= NGC 5 | url=http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=VII/26D/catalog&recno=84
| opera= [[Uppsala General Catalogue|Uppsala General Catalogue of Galaxies]] (UGC) (Nilson 1973)
| editore= VizieR Service | accesso=18-02-2010
}}</ref>
|v_radiale = 4971 ± 49
|tipo = Galassia ellittica
|classe = S0/E
|massa =
|pre_dimensioni_al =
Riga 32 ⟶ 45:
|dimensioni_pc =
|note_dimensioni_pc =
|absmag_v = -20,01
|note =
|nomi = [[New General Catalogue|NGC]] 20, [[Uppsala General Catalogue|UGC]] 84, [[Morphological Catalogue of Galaxies|MCG]] +05-01-036, [[2MASS|2MASX]] J00093270+3318310, [[Principal Galaxies Catalogue|PGC]] 679
}}
'''NGC 6''' (conosciuta anche con il nome di '''NGC 20''') è una [[galassia]] [[galassia ellittica|ellittica]] di quattordicesima [[magnitudine apparente|magnitudine]] visibile nella [[costellazione]] di [[Andromeda (costellazione)|Andromeda]] e distante dalla [[Terra]] circa 64,5 [[parsec|Mpc]] (210 milioni di [[anno luce|anni luce]]).
==Storia delle osservazioni==
'''NGC 6''' fu scoperta il [[18 settembre]] [[1857]] da [[William Parsons]].
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Found by Swift (List #2 on 20 Sept 1885) but his position was 1.1 tmin W and 47'
S of NGC 20 = U00084 = M+05-01-036 = CGCG 498-082. His RA offset is identical
to the error in his positions for N19, N21, N7831, N7836 also found the same
evening. Although the dec error is large, his description ("one of 5 st which
point to it is p nr") matches the chain of five stars just following N20, whose
position was accurately given by Schultz. The RNGC lists NGC 6 as nonexistent
but incorrectly equates it with N7831. See NGCBUGS for more info.
--
17.5": fairly faint, very small, round, small bright core, stellar nucleus. A
mag 11 star is just 30" E and a brighter mag 10 star lies 2.4' E. Second of
three with NGC 13 12' NW.
Schultz's micrometric position for NGC 20 matches U00084 = M+05-01-036 = CGCG
498-082. Swift later (20 Sept 1885) entered this galaxy in List #2 (NGC 6) but
his position was 1.1 tmin too far W and 47' too far S. His RA offset is
identical to the error in his positions for N19, N21, N7831, N7836 all found the
same evening. Although the dec error is large, his description ("one of 5 st
which point to it is p nr") matches the chain of 5 stars just following.
--
NGC 6 = NGC 20. On the night of 20 September 1885, Lewis Swift found
six objects. Four of these (NGC 19, NGC 21, NGC 7831, and NGC 7836; see the
notes for these, too) have mean offsets in their positions as published by
Swift, from the correct positions, of +1m 10s in RA and +8m 08s in Dec. A
fifth found later in the night, NGC 801, has offsets of -19s and -0.9m; Swift
clearly ``re-zeroed'' his telescope in the interim.
The sixth object, NGC 6, shares the right ascension offsets of the first four,
but its declination is about 45 arcmin too large. It's identity with NGC 20
is secured by Swift's note ``... one of 5 sts which point to it is pretty
near.'' The unmistakeable line of five stars stretches about 2 arcmin to the
east; Swift's ``pretty near'' star is about 15 arcsec east of the galaxy.
-->
==Osservazione==
Data la sua debole luminosità, per individuare NGC 6 occorre un [[telescopio]] da almeno 250 [[millimetro|mm]] di apertura.
Bright star 0.3 arcmin [north] of nucleus.
TYC 2264-35-1
==Caratteristiche==
Riga 47 ⟶ 108:
==Note==
<references/>
==Bibliografia==
Riga 60 ⟶ 121:
== Voci correlate ==
*[[Galassia]]
*[[Galassia ellittica]]
*[[New General Catalogue|Catalogo NGC]]
*[[Oggetti non stellari nella costellazione di Andromeda]]
== Altri progetti ==
{{interprogetto|commons=Category:NGC 6|etichetta=NGC 6}}
==Collegamenti esterni==
{{LinksNGC|6}}
{{NavNGC|6}}{{NavNGC|20}}
{{Portale|oggetti del profondo cielo}}
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