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NGC 6334 (14,373 of 18,816)


oc gc pln bn dn gx gxcl ast aka lost




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Cat's Paw Nebula

NGC 6334, Ced 140, Gum 62, RCW 127, Kes 49, Min 1-86, CTB 39, SNR G351.1+00.7, Cat's Paw Nebula, h 3678, GC 4288

RA: 17h 20m 49s
Dec: −36° 06′ 12″

Con: Scorpius
Ch: MSA:1439, U2:376, SA:22

Ref: SIMBAD, Corwin (2004)

(reference key)

Type: supernova remnant

Mag: B=?, V=?

Size: 20′
PA: ?

Image gallery

Photos  (2)

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Historical observations

John Herschel (1847) Cape Observations

Discovered by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "pB, vL, v irr oval, in which, though excentric, is a star 8m, whose place is that taken. One side of the neb is brighter than the other." On a second occassion he called it "vF, vL, vglbM, 5' long, 4' broad, out of middle is a star 8-9th mag or 9th mag, whose place is taken. The densest part of the nebula follows this star 4.5 seconds on the same parallel."

Published comments

Helwan Obs. Bulletin No 38 (1935)

F, 3'x1.5', mE 125deg, diffuse nebulosity, 8 stars p. (see M Wilson Report, 1921)

Duncan, J.C. (1940)

Red nebulae in the tail of Scorpio. Publ. A.A.S., 10, 48.

Cederblad, S. (1946) [VII/231]

Ced 140 (NGC 6334)

Position (1900): RA 17 13.7, Dec - 35 58

Star: -35 11457 (Mp=8.9:, V=8.0:, SpT=A0)

Spectrum of nebula: continuous spectrum (inferred from sp.t. of illuminating star)

Classification: Neb associated with mainly one star (which may be multiple) - star surrounded by a neb envelope without conspicuous structure (eg. lambda Scorpii)

Size: (not given)

Notes: "NGC 6334 = GC 4288 = h 3678. Disc. 1837. FA 61. (93 Pl 16, 243). R. -35 11457 = HD 156369."

Lindsay, E.M

Lindsay, E. M. () "NGC 6334, NGC 6357 and surrounding regions", IAJ, vol 3, p 182.

Sulentic & Tifft (1973)

The RNGC (Sulentic and Tifft 1973) notes that this is a diffuse nebula.

Photo index

Photo Index by Jim Lucyk: Sky&Tel. 3/66 p134, 136, Sky&Tel. 1/70 p6, Sky&Tel. 8/77 p94, Sky&Tel. 5/88 p479, Burnhams V3 p1728, Vehrenberg's Atlas of DS Splendors (3ed) p179.

Modern observations

Tom Lorenzin

Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "8M star at center of large (30' diameter) complex of nebulosity; N-filter helps mightily! N6357 (faint DIF NEB complex) 1.5 degrees to NE; good reference photo at VADSS-179."

[amastro] NGC 6334

Hi all, I found an observation I made from New Hampshire back in '89 with my 17.5-in and thought it might be of interest: 40W ( 50x) + UHC Interesting loose association of stars with nebulosity surrounding many. The nebulous patches are just visible with out the UHC, though close to the horizon. The UHC greatly enhances the view. Some of the diffuse patches seem linked by wisps. Resembles the Pleiades with dimmer stars and brighter nebulosity. -Jay- ------------------------------------------------------------------------

OK guys,

It's open season on this bad boy, now. I've recently asked both Brent and Brian (sorry for you guys getting it twice) about a rather odd part of the sky known as NGC 6334 in Scorpius. They were both very helpful, however, I figured some of you on the group may have some further insight. Mr. Gottlieb, Mr. Polakis, Mr. Riddle, you out there???

The adventure begins with me thumbing through Burnham's vol. 3 and running across the interesting photo on page 1728 of the "curious (which instantly meant trouble) field of nebulosity" known as NGC 6334. This socalled "curious" object was only mentioned one other time in the book, as being "vL,cF,Irr; complex field of neby 30" diam, with 8m A0-type star". It didn't immediately ring a bell, so I checked some previous notes. Not to be found! OK, so this is definitely "next time out" kind'a material, right? Time for a little research... The first source was the AGN, where the nebula was designated GN 2-8=RCW 127(Rodgers, Campbell, Whiteoak, 1960)=Marsalkova 309,310,311,312,315,316=NGC 6334! So, OK, it seems to have been studied a little bit, huh? Vehrenberg notes the object as being a rather large HII region in both the AGN and his ADSS, so the case is closed, right? WRONG! I then went to conveniently print out a Megastar chart, and the program took me to some 20' open cluster situated on the SE border of the nebula! Meanwhile the nebula was drawn in and designated only as RCW 127. Hmmm... Not good...

The reference used by Megastar for the NGC 6334 "open cluster" was Lynga's 1987 Lund Catalogue of Open Cluster Data. I took a look via ADS, and indeed there was a cluster known as Lund 745 with those coordinates and that size. And the catalogue x-referenced the cluster to C1718-360 (IAU) and (what else but...) NGC 6334! My copy of Uranometria 2000.0 showed the object as a nebula with an imbedded radio source, and unfortunately, the object wasn't included in the neither the OH&CDSO's nor any of the WSDOH's. I did find one reliable observation of the NGC 6334 nebulosity, which was by Steve G. on the NGC/IC Project home page, where the x-reference to the cluster Lund 745 was interestingly still used. My confusion was only taken to the nth power when I attempted a search using SIMBAD. It referenced NGC 6334 to a SNR (SNR351.1+00.7)! Well, that sort'a explains the radio source in Uranometria ;-) I searched for Sh 2-8 in SIMBAD, and it did reference that designation to actual nebulosity in the generally correct area. However, there seems to be no direct correlation between the two nebulae Sh 2-8 and NGC 6334 amongst any other professional literature at my disposal (I can't seem to locate the RCW catalogue on-line anywhere). Interestingly, I did find that most journal articles do refer to "NGC 6334" as an HII region.

Brent did verify that what John Herschel discovered back in ~1847 seems to indeed be nebulous, however, the actual discovery of the related open cluster and it's fictional(?) x-reference to the NGC 6334 nebula is still a mystery. There is a 1986 A&A paper that references the designation NGC 6334 to a young open cluster, so I can only assume that Lynga was not the first to propagate the x-reference between the two objects. Generally speaking, the nebula is quite large, heavily reddened, and otherwise very interesting. It obviously contains some strange diffuse radio source (a conveniently well-placed background SNR or some sort'a bubble of shocked gas within the heart of the nebula, itself, possibly???), a handful of IRAS sources, and even MASERS (presumably from YSO's?). Therefore, I have little doubt regarding the physical relationship between the Lynga open cluster and the nebulosity. However, the actual true and correct designations of each have obviously been confused at one point or another. Any insight concerning this would be greatly appreciated...





Given the complexity of the sources and the confusion between them, I suspect that Brian Skiff can help you unravel this one so that it makes some sense. Don't be surprised if Brian jumps in with a logical path to help you resolve these issues. He is a master at this!

Good Luck, and good hunting!



Well, I don't want to be the only "expert", and Jay M., Steve G., Dave R., and even Tom P. are pretty good in this area, too.



Hello folks -

I see that Jay McNeil has posted some further questions about NGC 6334. I thought it might be useful to provide here some of the additional information I was able to find while researching his original question to me about what this is and whether there is a star cluster here. I pointed out to him that I'm probably not as "up" as some of you (e.g. Brian Skiff and Dave Riddle) regarding the literature on nebula and the various catalogues, but I was able to find out a little. To make a long story short, NGC 6334 is a nebula, about 5' in size, included in Sh 2-8, about 2 degrees in size. NGC 6334 may or may not contain a cluster. If it does I haven't been able to figure out who discovered it and therefore what the name should be, but it is clear NGC 6334 should not be used for the name of the cluster (as Lynga did).

Anyway, more notes follow from my earlier message to Jay. Brian Skiff has also already posted some additional information (under the subject "NGC 6337 region"), including the info I give on the RCW paper. Let me know of any questions or comments - or if you're able to find out if there's really a cluster here and who discovered it!

Regards to all, - Brent


... As to NGC 6334 however, it is clear that this designation should be assigned only to the nebula. This is a John Herschel discovery, h 3678. His "Cape Observations" (1847) show two observations of this, and both plainly refer to this as a nebula, about 5' x 4', around an 8th magnitude or so star. He makes no mention of a cluster, and neither does the NGC description. So _if_ there is a cluster here, it should not be called NGC 6334.

Checking the DSS and his position shows that the star he had in mind must be HD 156738 at (2000.0) 17 20 52.66 -36 04 20.6 (SIMBAD: V=9.37, B7/B8Iab...). I estimate a position for the center of the nebula as 17 20 57.9 -36 03 40, and it appears about 5' in size. However, there is no obvious cluster or even grouping of stars here. About 20 stars total are visible within and to the edges of the nebula, with no concentration, and only a slight rise above the background numbers of stars. The nebula itself is barely visible with square root scaling but obvious with histogram equalization scaling.

As to a possible star cluster, at first I thought this was one of many cases where Collinder incorrectly assigned the NGC number of a nebula to some involved stars and (correctly or not) called it a cluster. However, I quickly found that this cluster is not in the Collinder catalogue. I haven't checked any intermediate catalogues (in time) but the cluster does not even appear in the Ruprecht, et al. 1981 compilation. Yet, as you point out, it is in Lynga's 1987 listing. Therefore I suspect that the discovery of this "cluster" is fairly recent, i.e. in the 1970's or 1980's.

I tried looking at the SIMBAD list of references for NGC 6334, but found there are order 150 of them. Not wanting to check all of them, I can only say that in checking the paper titles, the earliest reference to this as a cluster appears to be in the paper 1986A&A...159..223F. There it appears that since some stars had earlier been recognized as associated with the nebulosity that there were considered to be a cluster - but the backward reference for this assumption is not clear. If you wish, you might want to consider looking into this farther by looking at the earlier references listed by SIMBAD. In any case, it's not clear to me who "discovered" the cluster here (if real) or what it should be called.

By the way, SIMBAD gives the wrong position for the nebula - the position there ((2000.0) 17 19 58.0 -35 57 47) is about 1 time minute too far west (e.g. compared to John Herschel's position and mine given above).

As to the other nebula identities, I've never looked at the RCW paper. The text of it does not appear to be on-line at the ADS yet, but the full reference is:

Rodgers, A. W., Campbell, C.T., and Whiteoak, J.B. [1960]. "A catalogue of H-alpha emission regions in the southern milky way." MNRAS, 121, 103-110.

You should be able to find this in any reasonably large university or observatory library.

As to the Sh 2-8 identification, I do have a copy of Sharpless's catalogue here. His object 8 is listed at (1900.0) 17 14.7 -35 56, with diameter 120'. This position updates to (2000.0) 17 21.4 -36 02. This is obviously the same position as NGC 6334, but the size is much larger, showing that NGC 6334 is but a small part of Sh 2-8.

Sharpless also gives other identifications for Sh 2-8 as:

Reference Object numbers

Sharpless (1953) 7

Bok, Bester, and Wade (1954) 31800

H. M. Johnson (1955) 15, 16, 17, 18

Gase and Shajn (1955) 119

Gum (1955) 61, 62, 63, 64

So to summarize, NGC 6334 is a 5' diameter nebula, at (2000.0) 17 20 57.9 -36 03 40. It may or may not contain a cluster (but if it does it is very sparse or an infrared object), and in any case the "discoverer" and therefore the correct name of such an object appears to be unknown. Sh 2-8 is a large 2 degree HII region, which contains NGC 6334. ...

(end of message)


Jay! Down boy! For most of us, the nomenclature details won't really matter terribly much. For useful information about the field, it appears that the best work is by Neckel in the A&A (1978 A&A 69,51 and a follow-up paper 1984 A&A 137,58), which contains charts and photometry of brighter stars in NGC 6337 and neighboring NGC 6357 plus the tight cluster Pismis 24. More NGC 6357 is available from Lortet et al. (1984 A&A 140,24), which summarizes both the visible and radio morphology. Since Lortet is the originator of the "Dictionary of Astronomical Objects", he gives an appendix on the nomenclature and coordinates problems around 6357 (but not 6337).

For more details, Jay will want to hunt up on the ADS some additional papers:

1989ApJS...69...99S: STRAW S.M., HYLAND A.R. and McGREGOR P.J. (Astrophys. J., Suppl. Ser., 69, 99-140 (1989)) The centers of star formation in NGC 6334 and their stellar mass distributions.

1987ApJ...317..173H: HARVEY P.M., HYLAND A.R. and STRAW S.M. (Astrophys. J., 317, 173-179 (1987)) A near-infrared study of the NGC 6334-IV region.

Looking through the SIMBAD listings in the area suggests a large number of IDs need to be made with IR sources. Even a lot of the ordinary visually- bright stars need to be linked there. Hic labor, hic opus est!

Among other names like Sharpless, RCW, etc., the region was also catalogued by Colin Gum in his early southern HII survey (Memoirs of the RAS, 67, 155---a rare item that we have in the Lowell library). The RCW catalogue (Monthly Notices of the RAS 121,103) has 182 entries, so wouldn't be a terrible job to key-in oneself. They haven't scanned in the MNRAS back that far yet (though they do have volume 1 from 1827), but I would suspect that soon you'd be able to make your own version. If you want the RCW list photocopied, let me know, Jay, and I'll send it to you to work on.



Hi All

Jay's questions about the NGC 6334/RCW 127 objects prompted me to look into the matter a little deeper. I could find only a small amount of information in my (limited) personal library and at the risk of adding nothing to the already muddled situation, heres what I found.

The RCW catalogue gives the dimensions of 50' x 25' for RCW 127 with the note that it is "bright"- whatever that means - and composed of mainly 4 bright concentrations with faint extensions to 17h 10m -35d 30m (1950.0). Possibly these concentrations are the nebulous stars noted by van den Bergh and Herbst and catalogued as VDBH 85a,b and c. Rodgers,Campbell and Whiteoak cross reference RCW 127 with Gum 61,62 and 63- with only Gum 62 referred to as NGC 6334 and notes that is also known as Lund 140. Gum gives the dimensions of Gum 61 as 7' , Gum 62 as 8' and 63 as 25' . The Cederblad catalogue lists NGC 6334 as Cederblad 140 without giving any useful additional information.

When I last observed RCW 127 ( way back in 1992 at the TSP) with a 13.1" scope and an OIII filter I noted that the object(s) appeared as three distinct easily visible patches of nebulosity associated with 3 stars...

None of references (except the MegaStar program) refer to NGC 6334 as a galactic cluster - or note one in the vicinity.

The Emission Line Survey of the Milky Way images suggest that a Hydrogen Beta along with the OIII filter will enhance the visibility of RCW 127. Maybe this small bit of information will help resolve the puzzle of the RCW 127/NGC 6334 connection - or at the very least change the classification from FUBAR to SNAFU.

Dave Riddle

Steve Coe

Steve Coe, observing with a 17.5" f/4.5 at 100X, notes: "Faint, large, irregular at 100X. This emission nebula is the size of the 30' field in a 20mm Erfle eyepiece. The nebulosity has 15 stars involved. Using the UHC filter brings up the contrast of this object. There are four bright areas of the nebula, with the entire field aglow with dim nebulosity.

Contemporary observations

Auke Slotegraaf

1997 March 15

Jonkershoek. 11x80 tripod mounted. No moon. Large, irregular glow, like milky way patch.

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