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RA: 16h 33m 52.3877s
Dec: −48° 06′ 40.476″
Ch: MSA:1481, U2:407, SA:22
Type: bright nebula (HII region)
Mag: B=7.01, V=6.77
NGC 6164 and NGC 6165 are the two brightest lobes of the bipolar nebula associated with HD 148937, a hot, young, active star. These nebulae used to be called "planetaries", but we now know them to be the result of energetic winds from young, massive stars, rather than the dying gasps of dwarf stars like the Sun. These two fairly bright patches of ionized gas neatly flank the HD star. Deep exposures show more, though fainter, nebulosity closer to the star.
JH picked these up in South Africa, and noted the star as a double. If it is, it is a close double, not resolved on the short-exposure V plate scanned for the DSS.
Discovered by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "Neb violently suspected immediately preceding a double star."
Observations of southern nebulae. Transvaal Observatory Circular, No 2, 13
Ced 135a (NGC 6164)
Position (1900): RA 16 26.3, Dec - 47 53
Star: -47 10855 (Mp=6.7:, V=6.89, SpT=B0)
Spectrum of nebula: emission spectrum (inferred from sp.t. of exciting 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: "Ced 135 Two nebulae found by John Herschel in 1834 near -47 10855 = HD 148937 = Boss 22246. R. This star is probably responsible for the nebular light. Ced 135 a = NGC 6164 = GC 4206 = h 3633."
Chopinet, M. & Lortet-Zuckermann, M.C. (1972) A note to designations of planetary nebulae. Astron.Astrophys., 18, 166-167.
NGC 6164/5: RCW-107, PK 336𢤧, He 2-168.
The RNGC (Sulentic and Tifft 1973) notes that this is a planetary nebula.
G'day Mark and everybody else I thought that you might like to look up an article in the Astrophysical Journal Supplement Series 53:937-944 DEC 1983 The article is called Galactic Ring Nebulae Associated With Wolf-Rayet Stars. This article contains a list of some nebulae and finder charts to help locate them. These nebulae are wonderful to look at. Some of the southern observers may like to try the star HD148937 with its associated nebulae NGC6164/5. This star has a nebulae shaped like a barred spiral about it. The star appears to be pre main sequence and may have an age less than 350,000 years. (The astrophysical Journal 251: 126-132 DEC 1981) The finder chart associated with the article is over exposed. It does show the spiral nature of the nebulae. Of particular interest is the unusual loops of nebula found about 7' north east of the main object. Through Hector this nebula is VERY faint. It appears as an arc of nebulae about 10' long orrientated almost north-south. This is a great object but due to its position at -40 deg it will be very difficult to see from the continental US. Clear Skies Andrew Murrell
"The hot O-type star HD 148937 and its surrounding nebulosities [NGC 6164 & NGC 6165] present one of the most intriguing puzzles in the sky. This unusual complex of gas and dust lies on the Norma-Ara border .. HD 148937 lies some 4500 light-years from Earth and has an absolute visual magnitude of about -6 .. centered on the star is a strange S-shaped cloud, NGC 6164-6165, that is at least 7 light-years across. . . HD 148937 may be an older evolved O star that was wrapped in a cocoon of dust similar to that around Eta Carinae until 200,000 years ago. At that time radiation from the star broke through the absorbing shell, whose remnants are NGC 6164-6165, and began the evolution of the H II region and the cavity within it..."
Gerd Bahr-Vollrath (Noosa Heads, Queensland, Australia) observing with an 8-inch f/12 SCT, writes in the The Webb Society Nebulae and Clusters Section Report No. 10, July 1992: "One of the sadly ignored southern gourmet objects. Of particular interest is the fact that we are looking at a Wolf-Rayet shell, a rare object by any standards. It is difficult to spot, as the faint nebulosity surrounds a 6th magnitude star. Clean optics and an extremely transparent night were necessary to see anything at all. Immediately visible were two, apparently disconnected, bars of nebulosity, NW and SE of the central star, hence the two NGC designations. After careful study, faint, indistinct nebulosity immediately surrounding the central star became visible, connecting the two brighter bars. A challenging object!"
Instrument:12-inch Dobsonian Reflector Telescope.
Sky Conditions:The fainter parts of the Milky Way are barely visible.
Transparency of the Sky:Haziness only visible on the horizon.
Seeing:Atmosphere stable with little interference.
First Impression:This object looks like an emission nebula.
Chart Number:No.147(Extract taken out of "Atlas of the Southern Sky").
Size:26mm Super Wide Field Eyepiece:Field Of View:57'/3=19'.
20mm Ultra Wide Angle Eyepiece:Field Of View:50'/2.5=20'
19'+ 20'= 39'.
Size in Arc Minutes: 19.5'.
Nebula is 19.5'* 6.5'.
Brightness Profile:From the far outskirts of this nebula the central star grows slightly brighter.
This nebula is arranged in the shape of an unusual S.This is made up of blue to blue-white stars which gives light to this nebula.I have also found some dark lanes and patches in this nebula.I have on the other hand have found two hotspots either side of the star.
The Messier objects
The Bennett objects
The Caldwell list
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