U 431
14:30 to 15:30
-39° to -50°
Cen, Cir, Lup, Nor, TrA
Apr-Aug

FEATURED OBJECTS: Pismis 19, NGC 5662, Ru 111, BRABCMS 6, NGC 5715, NGC 5749, Hogg 18, NGC 5764, Slotegraaf De Kock 1, NGC 5800, NGC 5822, NGC 5823, BMT 15, Pismis 20, Lynga 3, Pismis 21, NGC 5925, NGC 5927.

Pismis 19
ESO134-SC005
RA 14:30:39
Dec -60°53.4'
Open cluster

NGC 5662
Mel 127, Cr 284, Rb 102
RA 14:35:11
Dec -56°32.0'
Open cluster

This cluster was discovered by Lacaille and included in his 1755 catalogue as Class III No. 8. In his half-an-inch 8x telescope he saw it as "two stars in nebulosity."

Dunlop 342 "A group of small stars of the 11th and 12th mag, with a multitude of minute stars mixt, extended S.p. and N.f."

h: "large, pretty brilliant, coarse, scattered cluster of Class VII which more than fills the field; 50 stars more or less 9..12th mag; chief star 7th mag, somewhat insulated, taken for place of cluster." On a second occasion, he noted the "place of a red star, the chief and centre of a fine bright but not rich cluster of about 30 stars 9..13 mag. This red or high yellow star is 8th mag."

Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 15' and the class as 2 3 pE.

11x80: This cluster appears obvious, even in strong moonlight, as an elongated glow with stars. (suburban skies, strong moonlight) [AS]

11x80: "B, vL, mE NNE-SSW, clearly resolved into stars. Stars of mixed magnitudes. One bright orange one, a few mediums, and many small stars. There are two triangular gorups, back to back, with a clear gap between them. The north-eastern triangle is marked on the U-chart as the cluster; here are at least six stars that are directly seen, and several others imagined. While sweeping the area, my eye is immediately drawn to this much elongated swathe of stars, almost like a pair of sweeping wings." (urban; seeing good; transparency below average; dew) [AS]

Ru 111
ESO134-SC010
RA 14:35:54
Dec -59°58.1'
Open cluster

BRABCMS 6
ESO176-PN001
RA 14:41:35
Dec -56°15.1'
Planetary nebula

NGC 5715
Mel 128, Cr 286, Rb 103
RA 14:43:24
Dec -57°31.0'
Open cluster

Dunlop 333: "a group of small stars with faint nebula. There is rather a gathering of the nebulous matter, about 10 arcseconds diameter, near the north side."

h: "cluster VII. Pretty rich, stars 11..13th mag, irregular, scattered,10' diameter, rather more comp M."

11x80: "Perhaps a nebulous presence between two 9.5 mag stars -- nothing certain." (urban; seeing good; transparency below average; dew) [AS]

NGC 5749
Cr 287
RA 14:48:54
Dec -54°30.0'
Open cluster

Dunlop 206 "a group of 8 or 10 pretty bright small stars, in the form of a letter Y, about 5' long, parallel to the equator, with small stars in it resembling faint nebula."

h: "cluster VII class; p rich, loose, irregular figure, 8', stars 19 and 11th mag."

11x80: Irregularly round mottled patch, flanked by two 9th mag stars. (suburban skies) [AS]

11x80: "Moderately easy as a L, pF, iR patch, well mottled, flanked by two 9th mag stars. A number of stars in twos in the field." (urban; seeing good; transparency below average; dew) [AS]

Hogg 18
ESO223-SC001
RA 14:50:41
Dec -52°16.0'
Open cluster

6-inch f/8.6 Newtonian: "An obscure cluster, one bright member (9.5m) with 8 fainter stars surrounding and extending off to the east. See the diagram from the STScI." (Franschoek mountain pass summit, obvious haze and thin clouds, sky fairly bright around horizon.) [AS]

NGC 5764
Cr 288
RA 14:53:35
Dec -52°40.0'
Open cluster

h: "a small elongated close group of vS milky way stars 3' long, 1.5' broad, so close and faint as to approach very near to the character of a nebula."

The RNGC (Sulentic and Tifft 1973) notes that this is a 12.5 mag open cluster.

6-inch f/8.6 Newtonian: "Perhaps seen as an extremely, extremely faint presence?" (Franschoek mountain pass summit, obvious haze and thin clouds, sky fairly bright around horizon.) [AS]

Slotegraaf de Kock 1

RA 15:00
Dec -55°
Asterism

I first noticed this milky way patch while sweeping the Circinus/Lupus a. Forming a right-angled triangle with NGC 5822 and 5823 was a third object. From north to south these are NGC 5822, Slotegraaf-de Kock 1, NGC 5823. This is also their order of brightness, NGC 5822 being the brighter. The 'new' object looks like a patch of rich milky way background, the small stars unevenly distributed, more dense towards the western side. It is roughly a third the size of NGC 5822, i.e. 10'; and has the same size as nearby NGC 5823.
A later binocular observation recorded: "Small tight knot of stars, next to or involving Y Lupus. Possible that more aperture will reveal it as just a chance stellar grouping, no cluster."
From the mountain plateau that forms the SAAO's observing site at Sutherland in the Karoo, I got a look at the grouping through a friend's 5-inch f/6 Newtonian. Under these pristine conditions, a 70' field of view, resolves the cluster as two poor groupings of little stars; no glow of unresolved background members. The grouping to the north-east consists of 6 small stars arranged in a triangle; the second grouping to the south-west is less well defined, and consists inter alia of 5 stars arranged like the pips on a playing card. [Sketch made]
My 6-inch f/8.6 Newtonian, from the summit of Franschoek Pass, shows that a short curved chain of 9th mag stars leads from NGC 5822 to this 'cluster', which even at 52x is shown to be nothing more than three close gatherings of stars; STScI/ESO/POSS image shows this well. However, in binoculars, the impression of a cluster remains.

NGC 5800
ESO223-SC011
RA 15:01:46
Dec -51°55.1'
Open cluster

h: "a pL cluster VII class; coarse, not comp, chief double star taken."

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

11x80: One of Herschel's Doubtfuls. I noticed this object earlier in the sweep before looking up its identity on the map. There are several stars in the binocular field which are of a similar magnitue. None of these exhibit a hazy envelope as does this star. I can imagine seeing a close companion to this star, contributing to the haze. (suburban skies, hazy, thin clouds) [AS]

NGC 5822
Mel 130, Cr 289, Rb 104
RA 15:05:04
Dec -54°19.0'
Open cluster

h: "cluster, vL, coarse, but rich and fine; diam in RA = 2 field in PD 25 (30' and 45'); stars 9, 10, 11, 12. General middle taken."

Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 40' and the class as 3 1 m.

Harrington calls this "unquestionably the best" deepsky object in Lupus. It is "a delightful open cluster for binoculars and fich-field telescopes. Viewing through 11x80 binoculars from the Florida Everglades (latitude 25 degrees) I recorded the group as a rich gathering of 8th mag and fainter stars set against the bright glow of other, unresolved cluster members."

11x80: (suburban skies) One of three milky way patches I swept up. The other, NGC 5823, lies due south, and the third, not shown on the U2000, lies half a degree south and half a degree west. NGC 5822 appears as a very large patch of rich milky way stars, some 40' across, with many small stars seen but with countless others seen only as a background glow. Overall the distribution of stars seems quite even. (suburban skies) Large, shy cluster of small and very small stars. No nebulosity of background glow. [AS]

11x80: "Giant (26') patch of textured sky, rough with star specks. Field very rich; the cluster simply fades into the background. Even when sweeping its an obvious large woolly patch." (urban; seeing good; transparency below average; dew) [AS]

5-inch f/6 Newtonian: In a 70' field of view, this wonderful cluster appears like a large, face-on spiral galaxy, with many long curved arms of stars. (pristine skies, Sutherland, SAAO plateau) [AS]

6-inch f/8.6 Newtonian: "Beautiful delicate cluster, which fills a 40 arcmin field well. Stars of 10th magnitude and fainter and scattered, making a coarse grouping, but nevertheless a cluster." (Franschoek mountain pass summit, obvious haze and thin clouds, sky fairly bright around horizon.) [AS]

NGC 5823
Mel 131, Rb 105
RA 15:05:47
Dec -55°34.0'
Open cluster

h: "Cluster class VII; a fine large cluster of separate stars 13..14th mag, 10' diameter; not much compressed in the middle; nearly fills the field."

Described in Union Obs. Circulars, 45-76, p 50. "Nebulae, clusters, etc. on Sydney Plates" as "Cluster of about 80 stars, 12-16 mag., 8' in R.A. and 10' in Dec."

Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 10' and the class as 3 2 m.

Sanford notes that this open cluster has "about 80 stars and is appreciated only with a telescope of 12-inch aperture or greater."

Phil Harrington (1990, Touring the Universe through Binoculars) notes "NGC 5823 lies just within the northern border of Circinus. It is a rich open cluster embodying some 100 stars shining at 10th magnitude and fainter and spanning 10' of arc."

ASV Journal Vol 24 No 3 June 1971: "small Y-shaped cluster in 4-inch 64x."

11x80: One of three milky way patches near the northern border of Circinus; NGC 5822 lies due north. NGC 5823 shows as a pretty evenly distributed patch of faint stars, rather like a piece of frosted glass. Like a smaller version of NGC 5822. The cluster appears larger using averted vision, and I estimate the overall size as 10'. Close north-west lies Slotegraaf-de Kock 1. NGC 5823 is the faintest of these three milky way patches. [AS]

11x80: "Large (14') vaguely round granular patch, one of three in the field. No concentration or clumped area." (urban; seeing good; transparency below average; dew) [AS]

6-inch f/8.6 Newtonian: "An immensely rich tear-drop shaped nebulous patch, with many stars resolved, of 11th magnitude and fainter. Although faint, it is quite well seperated from the background, because of the nebulous appearance." (Franschoek mountain pass summit, obvious haze and thin clouds, sky fairly bright around horizon.) [AS]

BMT 15
ESO135-SNR005
RA 15:13:29
Dec -59°00.3'
Bright nebula

Pismis 20
ESO135-SC006
RA 15:15:22
Dec -59°04.1'
Open cluster

Discovered by astronomers at the Union Observatory, Johannesburg. Described in Union Obs. Circulars, 45-76, p 50. "Nebulae, clusters, etc. on Sydney Plates" as "Chief of a little group of 16 stars."

Lynga 3
ESO135-SC007
RA 15:16:21
Dec -58°19.1'
Open cluster

Pismis 21
ESO135-SC008
RA 15:16:48
Dec -59°39.8'
Open cluster

NGC 5925
Cr 291
RA 15:27:41
Dec -54°31.0'
Open cluster

Dunlop 357: "a very extensive cluster of stars of mixed small magnitudes; the stars appear to be either congregating together in different parts of the cluster, or breaking up; there are several groups already formed, the whole cluster is composed of lines of stars, but no general attraction towards any particular point."

h: "a remarkable cluster, 20' diameter, R, very discrete, and composed of small groups of 2, 3, 4 stars, chielfy 11, 12 and 13th mag, sufficiently insulated from the rest of the pretty rich neighbourhood to be considered a cluster." On a second occassion he called it "a most numerous and beautiful milky way group or cluster covering a space of 1.5 or 2 fields diameter (20' or 30') entirely composed of double and triple stars, and distinct groups of 4 or 5 nearly of a size (10th and 11th mag) on a black ground. Perhaps 100 or 150 stars in field." His third observation was recorded as "Cluster VIII class. The field uniformly covered with insulted stars 11..14th mag, forming a rich cluster of 8th class, remarkable for the total darkness of he ground and absence of minute stars. Cluster much more than fills the field."

NGC 5927
ESO224-SC004, GCL-35
RA 15:27:59
Dec -50°39.5'
Globular cluster

Dunlop 389: Using a 9-inch f/12 telescope, he recorded it on 8 occasions, describing it as "a very fine round pretty bright nebula, about 3' diameter, gradually brighter towards the centre, and well defined at the margin: this is resolvable. With a power of 260 it has a beautiful globular appearance. The stars are considerably scattered on the south side."

h: "globular, B, L, R, gbM, diam in RA = 16 seconds. Comes up to a bright blaze in middle. Resolved by left eye. Stars 17th mag." On a second occassion he called it "globular, pB, fine highly condensed, vgbM, 3' diameter, clearly resolved. I see all the stars (15th mag) well."

11x80: "F, 7' (max) across, R, nebulous haze, in a very rich field. No distinct division into core/fringe." (urban; seeing good; transparency below average; dew) [AS]

6-inch f/8.6 Newtonian: At 52x, the field of this globular is well-sprinkled with 9-10th mag stars. In bright moonlight, the cluster is clearly but dimly seen as a R, pL, even glow; not sbM but rather a broad centre. Two very rough drift timings gave 10 seconds in time as the diameter. (suburban skies) [AS]

6-inch f/8.6 Newtonian: "Moderately large, soft glowing sphere, 3.7' in diameter with a broad centre (about 3' wide). Many small stars dot the surrounding field of view." (urban; seeing average - air pollution, dew; lim mag in 6-inch ~ 13.0) [AS]