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RA: 13h 25m 27.6152s
Dec: −43° 01′ 8.805″
Ch: MSA:933, U2:403, SA:21
Type: galaxy (Seyfert 2), E
Mag: B=7.96, V=6.98
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James Dunlop discovered this interesting and very peculiar galaxy from Paramatta, New South Wales, and included it as No. 482 in his catalogue of 1827. Using a 9-inch f/12 telescope, he described it as "a very singular double nebula, about 2.5' long, and 1' broad, a little unequal: there is a pretty bright small star in the south extremity of the southernmost of the two, resembling a bright nucleus: the norther and rather smaller nebula is faint in the middle, and has the appearance of a condensation of the nebulous matter near each extremity. These two nebulae are completely distinct from each other, and no connection of the nebulous matters between them. There is a very minute star in the dark space between the preceding extremities of the nebula: they are extended in the parallel of the equator nearly." He drew a sketch of the object, and observed it 7 times.
Sir John Herschel observed it at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "A most wonderful object; a nebula very bright; very large; little elongated, very gradually much brighter in the middle; of an elliptic figure, cut away in the middle by a perfectly definite straight cut 40 arcsec broad; pos = 120.3 ; dimensions of the nebula 5' x 4' The internal edges have a gleaming light like the moonlight touching the outline in a transparency." On his next sweep he observed it again, describing it as "Two nebulae, or two portions of one separated by a division or cut. The cut is broad and sharp. The two nebulae are very nearly alike. Perhaps the slit is larger towards the N.p. end, where there is a star between them. There is certainly a very feeble trace of nebula, an island as it were, running from this star between the sides of the slit. N.B. No 'moonlight effect' seen between the edges. Night very fine. Pos of the slit 120.3 The place taken is that of the star within the slit." His final observation recorded it as "A nebula consisting of two lateral portions, and no doubt of a small streak of nebula along the middle of the slit or interval between them, having a star at its extremity. Position of the slit 124.7 ; of the star, with another star near the nebula and south of it 332.3 ; others stars also laid down. A most superb calm night; objects admirably defined. Shown to a bystander (J.R.) who saw it as figured and described." Herschel carefully sketched the galaxy, and commented on it as "a very problematic object, and must be regarded at present to form a genus apart, since it evidently differes from mere 'double nebulae,' not only in the singular relation of its two halves to each other, (having each a well and an illdefined side, their sharply terminated edges being turned towards each other and exactly parallel) but also by the intervention of the delicate nebulous streak intermediate between them and lying in exactly the same general direction. It may perhaps be considered that the nebulae V.24 [NGC 4565] and I.43 [NGC 4594] offer some analogy of structure to this; but of so it is a very remote one, the nebulae constituting these objects being in both instances very unequal in size and brightness, and being individually merely elongated nebulae of the ordinary type, which these are not. On the other hand we have, in the completely resolved cluster,[NGC 6451], an object which, removed to such a distance as to appear nebulous, would present a considerably approach to it in point of general aspect."
There has been much controversy since Herschel's musings above over the nature of this object. In 1849, Sir John Herschel wrote in his "Outlines of Astronomy" that it was "two semi-ovals of elliptically formed nebula appearing to be cut asunder and separated by a broad obscure band parallel to the larger axis of the nebula, in the midst of which a faint streak of light parallel to the sides of the cut appears." In 1918, H D Curtis of Lick Observatory classified it as an edge-on spiral galaxy with dark lanes. Burnham notes that in a Helwan Observatory publication of 1921 it is described as a "large patch of structureless and possibly gaseous nebulosity, cut in two by a wide belt of obscuring matter, through which appear several stars and wisps of nebulosity." Hubble, in 1922, classified it as a local nebulosity. In 1932, Shapley and Ames included it in their famous catalogue of galaxies as an irregular system. Burnham notes that the "dark band is approximately 1' wide where it crosses in front of the nucleus, widening to about 2' on the southeast side of the galaxy. On the northwest the band becomes weaker and less regular, breaking into a chaotic mass of bright and dark clouds. The course of the dark lane is from PA 135 to 315 ."
Photo Index by Jim Lucyk: Sky&Tel. 1/75 p11, Sky&Tel. 1/83 p6, Sky&Tel. 3/84 p229, Sky&Tel. 5/72 p327, Sky&Tel. 5/81 p383, Sky&Tel. 6/79 p530, Sky&Tel. 6/80 p500, Sky&Tel. 8/86 (cover), Sky&Tel. 11/78 p389-391, Ast.Obj.for South.Tel. (Hartung, 1984), Astronomy mag. 7/83 p16, Astronomy mag. 6/75 p22, Astronomy mag. 11/84 p14, Burnhams V1 p567, Vehrenberg's Atlas of DS Splendors (3ed) p144, Hubble Atl.of Gal. (Sandage 1961) p50.
!! pB, 7'x5', a large patch of structureless and possibly gaseous nebolosity, cut in two by a wide belt of absorbing matter, through which appear several stars and wisps of nebulosity.
Reynolds, J.H. (1921) The spiral nebulae in the zone -40° to -90° (from the Franklin-Adams Plates). MNRAS, 81, 598.
"nebula, peculiar, broken, 5 *s involved"
Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.
De Vaucouleurs (1956) "Survey of bright galaxies south of -35° declination", Mem. Mount Stromlo, No. 13. (photographic study, plates taken with the 30-inch Reynolds reflector, 20-inch diaphragm).
This galaxy appears on page 50 of "The Hubble Atlas of Galaxies" by Allan Sandage (1961, Washington, DC).
Sidney van den Bergh (1961, Astronomical Journal, Vol 66) notes that this galaxy could be a radio source. He remarks: "Dark patches and bright knots. Similar to NGC 1316 and NGC 1275?"
This galaxy is a member of the fairly nearby Centaurus group of galaxies, which includes NGC 4945, 5102, 5128, 5236 and NGC 5253. Listed as No. 153 in Arp's "Atlas of Peculiar Galaxies" (Astrophysical Journal Supplement, vol. 14, 1966.)
Notes that this is a 7.5 mag galaxy. Their coded description reads BE,BM,LGDKLN CT.
de Vaucouleurs, G. (1975) Nearby groups of galaxies. In: Kuiper, G. (ed) Stars and Stellar Systems. Volume 9: Galaxies and the Universe. Chapter 14, p557.
5. The nearer groups within 10 megaparsecs
G4. NGC 5128 Group
Brightest members: 5236,5128,4945,5102,5068,5253.
Several large southern galaxies having low velocities may form a loose group or chain centred on NGC 5128, 4945, 5102, 5236 and NGC 5253 and possibly NGC 5068. Two (NGC 5102 and perhaps NGC 5128=CenA) are lenticulars, three are late-type spirals Sc-Scd and one (NGC 5253) is peculiar, possibly an I0 irregular (the BGC classificaion Imp is incorrect). The overall length of the chain is 30° = 2.1Mpc or 20° = 1.4 Mpc (excluding NGC 5068 which has the highest velocity). ... Even if this chain does not form a physical (bound) group, it is useful to obtain some estimate of the distance of NGC 5128.
Sandage, A. & Tammann, G. A. (1975) Steps toward the Hubble constant. V - The Hubble constant from nearby galaxies and the regularity of the local velocity field. ApJ, 196, 313-328. [1975ApJ...196..313S]
Sandage and Tammann (1975, Astrophysical Journal, 196, 313-328) includes this galaxy in the NGC 5128 Group. Members include NGC 4945, NGC 5068, NGC 5102, NGC 5128 & NGC 5236.
de Vaucouleurs, G. (1975) Nearby groups of galaxies. In: Kuiper, G. (ed) Stars and Stellar Systems. Volume 9: Galaxies and the Universe. Chapter 14, p557.
p 590: "The present data on nearby groups may nevertheless help to answer the simpler question:Are there isolated galaxies? ... out of the 60 galaxies in this objectively selected sample, only eight have not been associated with one of the 55 nearby groups, viz. NGC 404, NGC 1313, NGC 2903, NGC 3109, NGC 3521, NGC 6744, NGC 6946 & IC 5152. In addition there is a possibility that a few galaxies, such as NGC 1316, NGC 4594, NGC 4826 are not really members of the groups (For I, Vir Y, CVn I) to which they have been tentatively assigned. Furthermore, the reality of the NGC 5128 chain as a physical unit may be questionable; but then it is difficult to know where to stop in this 'dismemberment' of loose groups, and the local outcome of an overconservative attitude would be to exclude from consideration all but a few rich clusters and dense groups... on the other hand, several of the eight supposedly isolated galaxies might yupon further investigation turn out to be members of some of the nearer groups; in particular, NGC 404, NGC 3109 and IC 1512 should be examined for possible membership in the Local Group. Other (more remote) possibilities are NGC 1569, IC 342 and perhaps some heavily obscured systems as yet unrecognized. For example, IC 10, although long suspected, was only recently established as a Local Group member (Roberts 1962, de Vaucouleurs and Ables 1965). ... to the writer's knowledge, NGC 1313 and NGC 6744 in the southern sky, and probably NGC 2903 and NGC 6946 in the northern sky, are truly isolated galaxies not associated with any nearby group, although both are in the larger Local Supercluster."
Schmidt K.-H., Priebe A. & Boller T. (1993) Nearby galaxies. Revised machine-readable version of the catalogue. Astron. Nachr., 314, 371. [1993AN....314..371S]
Other names: "ARP153,E270-09". Inclination: (face-on, in degrees) 44 Total photoelectric blue mag 7.84 Total colour index 1.00 Logarithm of the angular diameter D25 (arcminutes) 2.41 Blue photographic magnitude 7.18 This galaxy is included in a sample of galaxies with velocity less than 500km/s with respect to the centroid of the Local Group. [Nearby Galaxies. Schmidt K.-H., Priebe A., Boller T. (Astron. Nachr. 314, 371 (1993))]
Centaurus A (PKS 1322-427) is the close active galaxy at a distance of 3.8 +/- 0.1 Mpc. ...The optical counterpart of Cen A is a giant elliptical galaxy (NGC 5128) which hosts a supermassive black hole with a mass M = 5.5 +/- 3.0 x 10E7 solar masses.
Hartung describes it as a "bright round luminous haze about 5' across, bisected by a clean dark bar about 1' wide in PA 130 in which is a faint luminous streak coming in N.p. Many stars are in the field, one being immersed in the southern region of theg nebula and one in the dark rift. Even a 3-inch shows this object plainly."
Burnham calls this a 7.2 mag peculiar spiral galaxy in Centaurus, 10' x 8', "most remarkable, very bright, very large, slightly elongated, dark central band, radio source." He notes that it is located 4.5 degrees north of Omega Centauri, and appears as a luminous sphere about 10' in diameter, crossed by a prominent dark obscuring band.
Houston writes: "Visually its bright 7th mag glow is some 10' in diameter with a wide belt of dark material dividing it in two slightly unequal halves. This belt shows well in a 4-inch telescope, and Ron Morales of Tucson, Arizona, has seen it with 7x35 binoculars." Houston also reports Morales' description as "very bright, large, round object, cut through the middle by a wide, dark lane."
Steve Coe, in "SACNEWS On-Line for May 1996", observing with a 17.5" f/4.5 Dobsonian, notes: NGC 5128 is bright, large, round and has a bright middle at 100X. The dark band across this galaxy is easy at 135X. There are several stars superimposed across the face of this object. This bizarre galaxy has been photographed many times because of the tormented shape of the dark lane across the bright body of this object. On that clear, sharp night so long ago, I was able to pick out some of that structure in moments of good seeing at 135X and 165X. You might hear this galaxy spoken of as Centaurus A, because of it is also a strong radio source and it got that designation from a radio survey done in the 1950s at Cambridge University in Britain. Wait for a great night then see if you can observe some of that fine detail at 13 hr 25.5 min and -43 01.
Steve Coe, using a 17.5" f/4.5, notes: "Bright, large, round and bright middle at 100X. The dark band across this galaxy is easy at 135X. There are several stars superimposed across the face of this object."
Harrington notes that it is "bright and large enough to be seen in 7x binoculars. When high in the sky the galaxy displays its dust lane well through giant glasses and small telescopes. Increasing to 10-inch or larger instruments, the lane begins to reveal irregularities along its fringes."
Sanford notes that a supernova reached 12th mag in the dust band area before fading in 1986.
Simon Tsang notes that in a 13-inch "the two bright hemispheres are separated by a dark lane of uneven width visible even at moderate powers. This dark lane is wider and more conspicuous than the dark lane in the Sombrero."
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "7.2M; 10' x 8' extent; very large; at first glance this looks like two separate objects; closer scrutiny shows large glow with broad equatorial dust lane; 9M stars on SE edge and to SW, 10' from core; !good supernova prospect! see photo at HAG-50."
Glen Cozens wirtes: "in a telescope two lobes can be seen with a dark lane between them, and a pair of stars shines in the southern lobe."
AJ Crayon, using an 8" f/6 Newtonian, notes: "is a spiral galaxy. It is 8m 3'x5' with no dust lane, has a bright middle of 2'x1' in position angle east with a star south of the bright middle at 100x.
Observer: Todd Gross
Your skill: Intermediate
Date and UT of observation: 1/1/98 11:00
Location & latitude: Cancun, Mexico
Site classification: Urban/Suburban
Limiting magnitude (visual): 5.1 zenith (est) 4.0 (est) in vicinity of object
Seeing (1 to 10 - worst-best): 5 (?)
Moon up (phase?): No
Weather: Clear to pt. cloudy
Instrument: 80mm APO refractor f/6 - f/l 480mm
Filters used: none
Personal Rating (for this aperture): C+
Best at around 70x, this was fairly easy to find only because it was near Omega Centauri (globular). I just ran the scope up to the north for a few degrees and looked for the nebulosity. It was a bit difficult at first, requiring averted vision to see the dark lane that runs roughly west to east and splits the approximately round patch in two pieces. Dark lane visible at 32 & 69x. Round patch of galaxy is relatively large, but at this aperture and focal length it still appears reasonably small, not as huge as Omega Centauri nearly, the largest globular I have ever seen.
Boston Meteorologist Todd Gross
= Arp 153
POSS: cf 1990 15cm obs: m11.0 * 16'.5 SW, m10.0 * 7' off maj axis to W. m12 * 4'.7 due N of center (not NE). m9 * SSE = SAO224131 (9.1, F0).
WDS: pair 10'.5 E = 1320.6-4232 (h4587): 9.4,9.5; 5".2; 87 (1934)
T&B: br * W: V=9.8; br * SSE: V=9.2; several others.
7x35mm - lg, pretty br diff glow flanked on E & W by m9 *s (fntr on W). seems elong ~N-S at least as long as sep of *s E&W. mod-wk even concen, occas glimpses of ~E-W dk lane. BS, 28May1995, TSP.
15cm - dk lane noted as notches. some *s seen in the brtr regions.
- dk lane obvious in pa110, 1' thick. 6' diam overall. S half much the lgr and more concen w/one * central and one on W just in dk lane. 150x: Nrn half much more extensive. br * is dbl and E part of lane is wider than W.
- consp @ 50x as two un=ly br glows w/broad dk bifurcation and m11.5 * sup on fntr Srn component. 80x: in dk lane is m12.5 * W of center. 165x: Srn portion seems brtr after all---lox views were dominated by embedded * washing out gx. one can imagine mod even concen were there no dk lane. overall size 5'-6'. BS, 14May1988, TSP.
- wow! 50x/80x show the outermost halo surprisingly well: it is 25'x15' in pa35, reaching two-thirds way to m10 * 17' SW and W to m10 * 8' away (it is the fntr and NErn of two m9-10 *s there). main body has familiar appearance: broad dk lane running SE-NW, becoming filled in going twd NW. sl hint of br streak w/in NWrn part parallel to lane. m9 * off SSE side, m10 * in SWrn lobe, m11 * in lane nr center, m12 * at edge of `core' on NE side. strong broad or mod even concen ignoring dk lane. SW lobe is more nrly a hemisphere, seems brtr than smlr NE lobe even w/m10 * sup. nice mod close pair 10' E. BS, 3Mar1990, LCO.
25cm - br. dk lane easily vis @ lox. 112x: dk lane flares at the ends being 90" wide. on N perimeter two fairly br *s are seen. the Nrn section is def brtr than the Srn. roughly a round cross-section. [N&S flipped here?]
Observing from the 1500 metre plateau of the SAAO observing site in Sutherland, shaking 11x80 binoculars show this to be a double nebula, somewhat like a double-cluster, appearing mottled.
A 15.5-inch reflector at 220x shows this beautiful object with its complete, bold dark band bisecting the nebula into uneven halves. The northern section is shorter and fatter than the southern half, which is a thin, bright band. The dark band is clearly broadest at the eastern tip, whilst the western tip has a star located just inside the extent of the band. The northern section contains two stars in the nebulosity. It bears a striking resemblance to a hamburger!
1984 December 30 01:55-02:02. PRG, 15.5-inch f/9 Newtonian, 220x.
Beautiful! A complete dark band cuts this nebula in two. Very nice! Northern half is shorter and fatter than southern half, which is a thin, brighter band. The band is broadest at the eastern tip. Two stars are embedded in the western tip.
From "Observing log, 2004 March 24"
Rifle Range, 6-inch f/8
I started off by briefly viewing NGC 5128, Centaurus A. This showpiece object deserves more time than I had at the moment, but it was as marvellous as Jupiter, in the same way that Pink Floyd is as marvellous as Bach. The galaxy's dark lane is always a pleasure to see. In one sense, one sees a brightish star (10 mag) from which blooms a broad nebulous fan of soft light, extending northwestward. The furthest extent of this oval nebulosity is snipped off, the decapitated piece clearly separated from the main body by a broad dark patch.
Sutherland (Huis Lana)
"Bertha" 12-inch f/4.8 Dobsonian (EP: 32mm, 25mm, 10mm, 6.3mm Plossls, 2x Barlow, 32mm Erfle)
Conditions: Clear, dark.
Probably the easiest way to find the famous Centaurus A is to start from beta Centauri, the second Pointer. Move up along the Centaur's leg to epsilon Centauri, and then continue in that direction until you hit omega Centauri – a hard-to-miss target in binoculars. Now, continue again in (roughly) the same direction for just 4.5° to arrive at your target. Enjoy. The final delight for the evening was Centaurus A. This glorious object measures 7.4' x 6.2' and consists of two bright lobes separated by a dark lane. The dark lane runs NW-SE and is about 2.7' wide. Both lobes are sharply cut off inside (creating the dark lane) while their bulging outer perimeters are hazy. The southernmost lobe is the smaller (about 4.4' wide at the base) and is perhaps better defined on its outer reaches than the northern lobe (more sharply terminated). The northern lobe fades off very gradually into the background, and tapers somewhat to the northwest. Three stars can be seen inside the southern lobe. A single small star lies just inside the north-western end of the dark lane (towards the southern lobe). A slim streamer of faint nebulosity runs centrally across the dark lane, starting at the single star. This streamer is wider at its north-western origin (extending towards the northern lobe). (D: 20090129/30.)
Stellenbosch (Paradyskloof rifle range)
6-inch f/8 Newtonian
Conditions: NELM 5.8 at the pole. Thin cloud in the distance.
This showpiece object deserves more time than I had at the moment, but it was as marvellous as Jupiter, in the same way that Pink Floyd is as marvellous as Bach. The galaxy's dark lane is always a pleasure to see. In one sense, one sees a brightish star (10 mag) from which blooms a broad nebulous fan of soft light, extending northwestward. The furthest extent of this oval nebulosity is snipped off, the decapitated piece clearly separated from the main body by a broad dark patch.
Date and Time: 18 June 2009, 21:10
Location: Prince Albert (Western Cape, South Africa).
Instrument: Orion XT10 10" f/4.7 Dobsonian Reflector
Eyepieces: 8mm Hyperion (150x, 27′ FOV), 17mm Hyperion (70x, 58′ FOV)
Sky Conditions: Seeing: 5/10. Transparency: Average.
Lots of moisture present in air.
Reasonably easy to locate using the 9x50 finderscope. Appears as a small reasonably bright smudge within 5° of Omega Centauri.
70x: Looks like a small round, reasonably bright diffuse patch bisected by a dark lane. Using averted vision the dark lane becomes more prominent. Centaurus A definitely has a "hamburger shape" as many people have remarked.
150x: At 150x magnification it is much easier to see details. The dark lane is now very prominent and appears to have very well defined straight edges. The lane is orientated slightly NW to SE and is widest towards the SE edge and narrows towards the NW edge.
The two diffuse sections now appear more elongated than round. One section is to the SW and the other to the NE. The SW section is larger and brighter than the NE section. One bright star is visible in superimposed to the SE above the SE section of the galaxy. A slightly dimmer star is visible towards the NW end of the dark lane.
A very bright mag 9 star is visible close to NGC 5128 towards the SE and various fainter stars are visible in the surrounding area.
Visual size estimated at roughly 6′ x 4′.
Location: Campsite (23 16 South 29 26 East)
Sky conditions: 7 magnitude clear.
Instrument: Meade 8" (Super wide angle 18mm eyepiece)
Date: 1997 April 5
One of my old friends. An excellent elliptical galaxy relative large with an uneven dark band separate this galaxy in two. A roundish haze structure with pinpoint stars in the starfield. In the one part two stars are visible, one a little brighter than the other one.
12-inch f/10 SCT (EP: 2-inch 32mm SW 95x 42' fov; 2-inch 14mm UW 218x 23' fov) and 16-inch f/10 SCT (EP: 2-inch 32mm SW 127x 32arcmin; 2-inch 14mm UW 290x 17arcmin; 2-inch 8.8mm UW 462x 11' fov)
One of my old friends. Excellent, very large, slightly oval galaxy, divided into two lobs (north and south) separate by an uneven dark band (218x). In the southern segment a 9th magnitude star is visible. Faint star about 10th magnitude embedded in the visible band on the western side. With 16" (290x) I could see that this part of the dark band is looped out with a kink whereas the eastern part of the band is fainter and fade out wider. With high power (290x) uneven knotted areas became evident. With averted vision the soft globs grow in size and two twin stars can be seen on the face of the northern nebula. James Dunlop discovered this interesting and very peculiar galaxy from Paramatta, New South Wales. (Mag 6.7; size 31.0' x 23.0'; SB 13.7; PA 31)
Date: 2007 03 17, 21:10
Location: Betty's Bay
Instrument: 8-inch Dobsonian, 17mm eyepiece
Sky: clear, heavy cloudbank far south.
Notes: Galaxy. At first I thought it was a globular cluster but then I noticed a dark lane through the middle. I had to double check a reference to determine whether I had indeed found the galaxy. Definitely the thrill of this evening's observing.
Instrument:12"Dobsonian Reflector Telescope.
Sky Conditions:Dark moon and stars magnitude 6 and fainter are barely visible with the naked eye.
Transparency of the Sky:The most clear sky possible.
Seeing:Excellent clean sky,limited star flickering and brilliant objects.
First Impression:Globular Cluster.
Chart Number:No.17(Extract taken out of "Atlas of the Night Sky").
Size:26mm Eyepiece:Field Of View:57'/8=7.1'.
20mm Eyepiece:Field Of View:50'/7=7.1'.
Brightness Profile:Medium Low Surface Brightness.
Challenge Rating:Easy to observe in a dark sky under a large telescope,but somewhat difficult to observe in a medium telescope under light polluted skies.
The galactic nucleus has an elliptical appearance where by the dust lanes are bisected in the middle of the galaxy which gives this galaxy the appearance of a hamburger.Close to the vicinity of this galaxy there is a moderate amount of stars close to this galaxy.No other dark lanes are noted on the outskirts of this galaxy.No darker areas of uneven brightness are noted within this galaxy.
The Messier objects
The Bennett objects
The Caldwell list
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