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RA: 18h 09m 56.8s
Dec: −24° 06′ 23″
Ch: MSA:1392, U2:339, SA:22
Ref: NGC/IC, SIMBAD
Type: bright nebula
Mag: B=?, V=?
Size: 15′ x 10′
Discovered by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "vF, L, oblong, 5' long, 3' broad, place of a double star involved, 6 other stars near. Query, if involved."
F, 20'x10', mE 130deg, diffuse nebulosity with absorption lanes, mB round stars CD 12536 and CD 12517.
Ced 154f (NGC 6559)
Position (1900): RA 18 3.8, Dec - 24 8
Star: -24 13984 (Mp=9.93, V=9.78, SpT=B1)
Spectrum of nebula: emission spectrum (observed)
Classification: Neb associated with mainly one star (which may be multiple) - star surrounded by a neb envelope with conspicuous structure (eg. IC 5146)
Notes: "Ced 154 The group of nebulous stars following M 8. R. There has been some confusion in the literature as to the proper identification of these objects. Ced 154 f = NGC 6559 = GC 4384 = h 3733 = h 1996 = The nebula around the stars -24 13984 (= HD 166056), and -24 13985. In (88) Pl 52 the first mentioned star is erroneously given as -24 13990. (114,294)."
A catalogue of H-II regions. Astrophys.J.Suppl.Ser., 4, 257-279.
"Appear to be connected with M8"
Beverly Lynds (Astrophysical Journal Supplement, No 105, 1965) in her Catalogue of Bright Nebulae, notes that this nebula is bright, more promiment on the red POSS plate, and has a maximum size of 15' x 10'.
Bernes, C. (1977) A catalogue of bright nebulosities in opaque dust clouds.
Bernes 7 = NGC 6559 / IC 1274 / IC 1275 / IC 4685.
The RNGC (Sulentic and Tifft 1973) notes that this is a diffuse nebula.
by Jim Lucyk: Vehrenberg's Atlas of Galactic Neb-2 p28, 29, 30.
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: " [NGC 6559, IC 1274, IC 1275, IC 4684, IC 4685] This complex of faint nebulosity lies about one degree east of M8, and deep photographs reveal that it seems connected to its more prominent neighbour. Low magnifications and a UHC filter were necessary to see indistinct faint patches of nebulosity, most of which seem associated with groups of stars."
Coe, observing with a 13" f/5.6, notes: "Faint, large, elongated E-W, double star involved at 100X. This nebula can be seen without the UHC filter, but is much more obvious with the filter in place. The nebula is brightest on the south side."
Location: Jonkershoek Nature Reserve, Assegaaibosch Station
Date: 1998 July 31 / August 01, 01:00-02:40 SAST
11x80 tripod-mounted binoculars (9.5 mag stars at times not easy)
Sky conditions: Mediocre (transp. low, seeing average, dew) The skies are showing the effects of the combination of pollution (mainly from a nearby wood-processing plant) and a stable inversion layer, turning daytime skies grey-blue, and night skies ashen.
Too subtle to be seen tonight.
The Messier objects
The Bennett objects
The Caldwell list
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