U 451
12:36 to 13:48
-61° to -72°
Aps, Cen, Cir, Cru, Mus
Feb-Aug

A VERY COMPLEX MAP, THIS ONE. Dark and bright nebulae, open and globular clusters, the whole gamut. Unlike most Uranometria maps, this one is not dominated by faint galaxies -- only five are listed in the ESO/U, and none made it into the NGC.

Highlights include the "brilliant" Coalsack, which sits alongside the delicate Cederblad 122. Just to the south in Musca lies the intruiging NGC 5189 (Bennett 62), while further down is the globular cluster NGC 4833 discovered by Lacaille in the 1750's.

FEATURED OBJECTS: Coalsack, Harvard 6, NGC 4609, Hogg 15, Gum 45, ESO095-PN016, BRABCMS 4, Gum 46, ESO095-RN?018, ESO065-SC003, vdBH 140, NGC 4815, NGC 4833, IC 4191, ESO096-PN003, Danks 1, Ld 757, vdBH 144, AL 1, NGC 5045, ESO132-EN003, Harvard 8, ESO132-EN004, Stock 16, Wray 17-59, Ru 107, Ld 807, NGC 5120, Ru 166, Basel 18, ESO065-SC007, Hogg 16, NGC 5155, Cr 271, Cr 272, Tr 21, PK307-03.01, NGC 5189, Ld 848, Pismis 18, IC 4291, vdBH 150, ESO097-PN001, Ld 894, vdBH 151, ESO133-PN001, NGC 5269, Ld 991, NGC 5281, Cr 277.

Coalsack
Dark nebula

Naked eye: To the naked eye, the Coal Sack appears like a large, dark puddle in the Milky Way, next to the Southern Cross. It has a round, pointed, tear-drop shape, about as long as the long arm of Crux. The Jewel Box lies right on the edge of this dark cloud. The Coal Sack is just about the right size for the LMC to fit inside, and looks as if the Large Cloud was torn off here and cast aside. (suburban skies) [AS]

Hartung: “Crux lies almost wholly in the Milky Way which is very bright in this region and so renders conspicuous the large irregular dark nebula immediately Sf known as the Coal Sack. This dust nebula is about 7° x 4° and lies at a distance of 170pc ... Projected on it is a small star CPD 3376 mag 6.5, which on a clear dark night is distinctly visible to the unaided eye and may therefore be used as a test object.”

Harrington: “the most famous naked-eye dark nebula in the entire sky. Covering an area approximately 5° x 7°, it looks like a huge dark hole in the radiant star clouds of the Milky Way just east of Acrux. It more than fills the field of most binoculars. While most amateurs see the Coalsack as a homogeneous black patch, intricate filamentary detail may be spotted throughout by sharp-eyed observers. However, one must wait for a dark night before these delicate features will reveal themselves. At a distance estimated to be about 550 light years away, the 60-light-year wide Coalsack is believed to be the closest obscuring nebulosity to Earth.”

The Coal Sack is clearly seen on Plate 5 of Solon I Bailey’s photograph from “The Southern Milky Way”, Annals of Harvard College Observatory, Vol 72, No. 3. “The Coal Sack is seen here to be very irregular in shape and to be much richer in stars than non-galactic regions. It appears dark to the eye only by contrast with the adjacent brilliant portions of the Milky Way. Many dark lanes are shown on this plate. One of these forms a long extension to the Coal Sack in a south preceding direction.” To Plate 6, Bailey comments: “The most striking feature of this region are the rifts in the Milky Way south of, and following, Alpha Centauri. The former somewhat resembles the Coal Sack. Both this and the great break following alpha Centauri are well shown in the drawings of Gould and others.”

Harvard 6
ESO065-SC002, Cr 261
RA 12:37:56
Dec -68° 22.4'
Ocl

NGC 4609
Cr 263, Coalsack cl.
RA 12:42:24
Dec -62° 57.0'
Ocl

A pretty bright star on the border of the Coalsack is kept company by two open clusters, to its west is the Coalsack cluster, NGC 4609, and directly opposite on the east is Hogg 15.

Discovered by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "Cluster class VII. Stars 11..13th mag; about 6' long and 4' broad; has 10 stars 11th mag, and some 20 or 30 smaller. It occurs in the midst of the black space following Alpha Crucis, which is by no means void of stars."

Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 4.5' and the class as 2 2 p.

ASV Journal Vol 24 No 3 June 1971: "visible in 2-inch 64x."

11x80 binoculars: Soft fuzzy glow; could as well just be 2 or 3 very faint stars. This cluster is readily seen with averted vision; however, looking directly at the bright star to its southeast, the cluster vanishes. Using averted vision, the cluster and star look like an artistic, stylized impression of a comet: the star forms the nucleus, and the cluster the tail. The part of the cluster nearest the star forms a prominent north-south bar, and the other cluster members extend away to the northwest forming an irregular triangle. (suburban skies) [AS]

6-inch f/8.6 Newtonian: A poor but obvious cluster on the edge of the Coalsack. About 13 stars in a north-south elongated grouping 1.5 by 4.5 arcmin large. It is well separated from the background and exhibits no particular concentration. Moderate brightness range, with half-dozen similar magnitude stars, the rest slightly fainter. At both the northern and south end of the grouping lies a small triangle of stars. Outside the cluster, 4' to the southeast, lies an orange 7th mag star. (suburban skies, 6.0 naked eye) [AS]

10-inch f/5 Newtonian: At 70 power this cluster appears small, very poor, scattered but distinctly shaped -- the seven brightest stars form an oblong bow-tie. (suburban skies) [AS]

15.5-inch f/9 Newtonian: Cluster of stars with a distinct box shape, elongated north-south, with a member in the middle, flanked on its north and south by two triangular patches. About a dozen 9-11th mag stars make up this sparse cluster, which forms a nice contrasting pair with Hogg 15. (suburban skies) [AS]

Hogg 15
ESO095-SC015
RA 12:43:35
Dec -63° 06.2'
Ocl

A pretty bright star on the border of the Coalsack is kept company by two open clusters, to its west is the Coalsack cluster, NGC 4609, and directly opposite on the east is Hogg 15.

6-inch f/8.6 Newtonian: Maybe three stars in a narrow triangle, 0.8 arcmin across. Just east is a 11th mag False Cross asterism; Hogg 15 thus corresponds to the position of NGC 2516. (suburban skies, 6.0 naked eye) [AS]

10-inch f/5 Newtonian: A 70-power eyepiece shows this cluster as a very small, faint nebulous patch, looking like two small, faint stars, giving it an elongated appearance. (suburban skies) [AS]

15-inch f/9 Newtonian: Even at 220x, this cluster is a terribly inconspicuous, tiny, compact collection of about four 11th mag stars. Following closely is a conspicuous asterism of the False Cross. (suburban skies) [AS]

Gum 45
RCW 69
RA 12:44:04
Dec -62° 28.9'
Neb

RCW gives the dimensions as 5x3 arcmin and notes that it is moderately bright. (Rodgers, A. W., Campbell, C. T. & Whiteoak, J. B. () "A catalogue of H-alpha emission regions in the southern Milky Way", Vol 121, p103-110.)

ESO095-PN016
PK302-00.01
RA 12:45:46
Dec -62° 59.2'
Pln

BRABCMS 4
ESO095-PN017
RA 12:48:32
Dec -63° 50.0'
Pln

Gum 46
RA 12:50:29
Dec -61° 34.7'
Neb

ESO095-RN?018
RA 12:51:22
Dec -63° 18.3'
Neb

ESO065-SC003
RA 12:51:37
Dec -69° 43.8'
Ocl

vdBH 140
RA 12:53:11
Dec -67° 10.0'
Ocl

NGC 4815
Cr 265
RA 12:58:04
Dec -64° 56.0'
Ocl

Discovered by h; recorded it as "cluster, rich, pS, resolved; irregular; gbM, 3', stars 13..18th mag." On a second occassion he called it "Class VI, p rich, irregular figure, gbM, 3', stars vS, comparatively insulated; has 2 bright stars 8-9th mag and 9-10th mag."

Curiously, in 1898 R.T.A. Inness observed this cluster with the 7-inch Merz refractor at the Royal Observatory, Cape of Good Hope. He wrote: "h calls this a cluster. It now looks like an irregular nebula surrounding two stars". Then, in 1902, he writes "It is doubtful if this (which h calls a cluster) is resolvable in the 7-inch. It is involved with, but to the South of, the two stars CPD-64 2088 and 2090...".

Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 4' and the class as 1 3 m.

11x80: Unlike the many other 8th mag stars around this area, this point-like source has a definite, hazy envelope, giving it the appearance of a small globular cluster. It is easily seen because it is so 'different' to the other stars. (suburban skies) [AS]

NGC 4833
ESO065-SC004, Lac I-4
RA 12:59:36
Dec -70° 52' 29''
Gcl

This globular was discovered by Lacaille and included in his 1755 catalogue as Class I No. 14, classifying it as a nebula. In his half-an-inch 8x telescope he saw it as "a small faint comet."

James Dunlop observed it from Paramatta, New South Wales, and included it as No. 164 in his catalogue of 1827. Using a 9-inch f/12 telescope, he described it as "a pretty bright round nebula, about 4' diameter, moderately condensed to the centre. This, with the sweeping power, has the appearance of a globe of numerous matter with very small stars in the north following margin. But with a power sufficient to resolve it, the globular appearance vanishes in a very conciderable degree; and the brightest and most condensed part is to the preceding side of the centre, with the stars considerably scattered on the N.f. side. Resolvable into stars of mixt small magnitudes. A small nebula precedes this." He observed the cluster on 5 occasions.

Observed by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "globular, B, L, R, gbM, stars 14th mag, and one 7th mag N.p. the centre; a fine object." On a second occassion he called it "globular, pB, L, p rich, at first gradually, then vspmbM; diameter of the bright part 3', of the loose stars 10'; stars 12..16th mag, and one large one 7th mag, 3' or 4' north of the centre."

ASV Journal Vol 24 No 3 June 1971: "easy in 4-inch 64x."

11x80: This cluster is easy in binoculars, lying north and slightly west of the yellowish Delta Muscae. Has a small star involved north-east. Even in strong moonlight, the globular and the companion star are easily seen. Interesting contrast with NGC 4372 some 3 degrees west. (suburban skies, 6.0 naked eye) [AS]

15.5-inch f/9 Newtonian: Very loose and well spread out at 220x, star-poor with faint stars resolved at the centre. (suburban skies) [AS]

IC 4191
ESO096-PN002, PK304-04.01
RA 13:08:45
Dec -67° 21.4'
Pln

ESO096-PN003
PK305-00.01
RA 13:10:03
Dec -62° 22.8'
Pln

Danks 1
C1310-624
RA 13:12:10
Dec -62° 40.0'
Ocl

Ld 757
RA 13:12:23
Dec -65° 17.0'
Ocl

vdBH 144
RA 13:15:06
Dec -65° 55.0'
Ocl

AL 1
ESO096-SC004
RA 13:15:14
Dec -65° 55.2'
Ocl

(See Andrews, A.D., Lindsay, E.M., 1967, Irish Astron. J. 8, 126.)

NGC 5045
ESO096-SC005
RA 13:17:04
Dec -63° 24.8'
Ocl

Discovered by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "a great cluster, or a surprisingly rich portion of the milky way. It contains 34 stars 11th mag, and perhaps 150 or 200 more of less magnitudes in field."

The RNGC (Sulentic and Tifft 1973) notes that this is a nonexistent object. Their coded description reads NOCL S.

ESO132-EN003
RA 13:18:08
Dec -62° 40.9'
Neb

Harvard 8
ESO096-SC006, Cr 268
RA 13:18:13
Dec -67° 04.9'
Ocl

ESO132-EN004
RA 13:19:04
Dec -62° 34.4'
Neb

Stock 16
ESO132-SC005
RA 13:19:27
Dec -62° 37.4'
Ocl

Wray 17-59
ESO096-PN007
RA 13:19:28
Dec -66° 09.1'
Pln

Ru 107
ESO096-SC008
RA 13:19:45
Dec -64° 56.5'
Ocl

Ld 807
ESO132-SC006
RA 13:24:39
Dec -62° 29.4'
Ocl

NGC 5120
ESO096-SC011
RA 13:25:39
Dec -63° 27.5'
Ocl

Discovered by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "cluster class VI; oval; 4' long, 3' broad; stars 12..16th mag; an extremely rich clustering patch in the milky way, which is here superb."

The RNGC (Sulentic and Tifft 1973) notes that this is a nonexistent object. Their coded description reads NOCL S.

Ru 166
RA 13:26:00
Dec -63° 24.0'
Ocl

The SAC 4.0 database comments: "Asterism?"

Basel 18
RA 13:28:16
Dec -62° 21.0'
Ocl

ESO065-SC007
RA 13:29:17
Dec -71° 16.1'
Ocl

Hogg 16
ESO132-SC008, Basel 19
RA 13:29:17
Dec -61° 12.2'
Ocl

11x80: A dim nebulous star, quite easy to see even in suburban skies. Under pristine skies, it is brighter, appearing as a small faint patch about 90 arcseconds across. [AS]

6-inch f/8.6 Newtonian: Low-power sweeping eyepiece (50', 42x) shows at first glance a compact, small grouping of 10th mag and fainter stars, well-defined and neatly insulated (II 1 vp). There are two short rows of 11th mag stars, running east-west; the southern row has three stars (one of which is noticeably fainter), the northern chain has only two stars. This small grouping fits comfortably into a high-power 8' field since it is about 5' across. Further west of these two rows is a scattering of fainter stars -- are these still part of the cluster? (suburban skies, 5.6 naked eye, seeing good) [AS]

NGC 5155
ESO096-SC013
RA 13:29:35
Dec -63° 25.5'
Ocl

Discovered by John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "A portion of the milky way broken up into clustering masses of astonishing richness. There must here be at least 200 or 300 stars in the field, none greater than 10th mag."

The RNGC (Sulentic and Tifft 1973) notes that this is a nonexistent object. Their coded description reads NOCL S.

Cr 271
ESO096-SC014
RA 13:29:54
Dec -64° 12.1'
Ocl

11x80: Quite easy to see; a starlike point with a mottled envelope. (suburban skies) [AS]

6-inch f/8.6 Newtonian: A delicate vaguely round puff of fine starlight, 6 arcmin across, on a very rich field. Wide range in brightness -- there is one very bright (10th mag) star on the southern tip, then perhaps half-dozen 11th mag, all on a sea of fainter stars. Not well detached from the background. Best seen in the lower-power (52x, even 72x) eyepieces; 108x is too much. Southwest of the cluster lies a neat, equal double star. (suburban skies) [AS]

Cr 272
ESO132-SC009
RA 13:30:24
Dec -61° 19.0'
Ocl

11x80: Round patch of starglow, 7.5 arcmin across. (pristine skies, Sutherland, Karoo) [AS]

6-inch f/8.6 Newtonian: A wide, scattered poor cluster of 11th mag stars. Ill-defined grouping measuring 5' by 3'. About ten 10th mag stars noted. Typical Collinder-type object; I make the Trumpler class to be IV 2 p. (suburban skies, 5.6 naked eye, seeing good) [AS]

Tr 21
ESO096-SC015, Cr 274
RA 13:32:13
Dec -62° 47.6'
Ocl

Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 5' and the class as 1 3 p. He notes: "Found on Franklin-Adams Chart. Small dense group of a few stars around two stars of 10th mag. Not well resolved on the chart."

11x80: A small star with hazy envelope fading off to the northeast. Quite easy to see. (suburban skies) [AS]

PK307-03.01
RA 13:33:30
Dec -65° 45.4'
Pln

NGC 5189
IC 4274, Gum 47
RA 13:33:31
Dec -65° 58.6'
Pln

This object was tentatively identified by John Herschel as Dunlop 252. James Dunlop observed from Paramatta, New South Wales, using a 9-inch f/12 telescope. His description for this object, which he observed twice, reads: "A very faint nebula, about 25 arcsec diameter. It is very near a star of the 8th mag, and near the N.f. extremity of a crescent of very small stars."

Herschel observed it at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "A very strange object. A nebula of oval figure, but having a central and brighter axis somewhat curved, and terminating in two masses brighter than the rest; diameter about 90-100 arcsec. It involves 3 stars, one of which with 320 power is double. The principal star is 10th mag, the others extremely small; a multitude of other stars in field."

Hartung calls it a "remarkable gaseous nebula ... it lies in a beautiful star field and is bright, about 1.5' x 1' in PA 260 with irregular internal structure and three stars immersed. There is a knot of bluish light following, from which a bright curved bar passes axially west ... three-inch telescope shows the irregular structure."

The nebula was described by Colin S. Gum, in A Survey of Southern H II Regions published in the RAS Memoirs, Vol. LXVII. He identifies his No. 47 with the object, noting that it is also catalogued as Cederblad 123. He gives its size as 3' x 2'. In his Notes he writes: "Has been classified as a doubtful planetary nebula [B. Voronstov-Velyaminov, Astron. Journal of the Soviety Union, Vol. 40, 1934.] A photograph by Evans and Thackeray and a drawing by Shapley show a very complex diffuse and knotted structure with no recognizable exciting star. The surface brightness is very high. A peculiar object."

The nebula is also included in the catalogue by Rodgers, Campbell and Whiteoak as RCW 76. they report the same angular dimensions as Gum, and comment it with "Planetary?" In a Research Note published in Astronomy & Astrophysics Vol 18 (1972) the authors note that PK 307-3 1 is synonymous with RCW 76, NGC 5189, IC 4274, He 2-94 and Th 2-C.

ASV Journal Vol 24 No 3 June 1971: "central part just visible in 3-inch."

Ld 848
RA 13:33:58
Dec -64° 31.0'
Ocl

Pismis 18
ESO132-SC014
RA 13:36:31
Dec -62° 12.8'
Ocl

The SAC 4.0 database comments: "Asterism?"

IC 4291
ESO132-SC015
RA 13:36:56
Dec -62° 05.6'
Ocl

In 1902 R.T.A. Innes was observing with the 7-inch Metz refractor of the Royal Observatory at the Cape of Good Hope when he found a "small round nebula about 1' in diameter, brighter towards the centre".

vdBH 150
RA 13:37:54
Dec -63° 20.0'
Ocl

ESO097-PN001
PK307-04.01
RA 13:39:35
Dec -67° 51.1'
Pln

Ld 894
ESO097-SC002
RA 13:39:40
Dec -64° 19.7'
Ocl

vdBH 151
RA 13:40:17
Dec -61° 42.0'
Ocl

ESO133-PN001
PK309+00.01
RA 13:42:38
Dec -61° 54.3'
Pln

NGC 5269
ESO097-SC004
RA 13:44:44
Dec -62° 54.7'
Ocl

Discovered by John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as a "cluster class VII. Poor, large, loose irregular figure; fills field; stars 12th mag." On a second occasion he recorded a "fine rich milky way group, or rather outlying cluster of a much finer cluster following it."

The RNGC (Sulentic and Tifft 1973) notes that this is a nonexistent object. Their coded description reads NOCL S.

Ld 991
RA 13:45:24
Dec -62° 00.0'
Ocl

NGC 5281
Mel 120, Rb 98
RA 13:46:34
Dec -62° 53.0'
Ocl

This open cluster was discovered by Lacaille and included in his 1755 catalogue as Class I No. 1. In his half-an-inch 8x telescope he saw it as a "small indistinct spot."

James Dunlop observed it from Paramatta, New South Wales, and included it as No . 273 in his catalogue of 1827. Using a 9-inch f/12 telescope, he described it as "a curved line of small stars, about 1.5' long, with a star of the 7th mag in the north extremity; a group of extremely minute stars on the preceding side of the crescent, and a multitude of very minute stars extended preceding and following." Dunlop sketched the cluster and observed it on 7 occasions.

John Herschel at the Cape of Good Hope observed it with an 18-inch f/13 speculum telescope. He recorded it as "Cluster class VII. Small, compact irregularly roundl 1 8th mag star, and 15 or 20 smaller in a knot. No. 1 in Sweep 578 [NGC 5269] is an outlier of it." His second observation was recorded as "A brilliant, compact milky way cluster. Rich, irregular figure, gradually brighter in the middle; 10'; stars 10..12th mag."

Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 4' and the class as 1 3 m.

Hartung notes that a "30cm shows it as a beautiful scattered cluster of fairly bright stars merging into a fine field and concentrated at the centre in a pattern of two crossing curved lines of brighter stars, yellow, bluish, white and orange. The central region is about 4' across and 10.5cm shows it well; on a clear dark night this is a most lovely field."

11x80: Binoculars show a rich field, with handful of brightish stars scattered around. One of these stars, however, just cannot be focused and remains hazy. Averted vision shows, around this star, a soft glow of starlight like a halo. (suburban skies) [AS]

Cr 277
ESO097-SC006
RA 13:47:59
Dec -66° 03.5'
Ocl