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RA: 18h 25m 42.45s
Dec: −23° 12′ 10.6″
Ch: MSA:1391, U2:340, SA:22
Type: planetary nebula
Mag: B=11.9, V=9.9
Synonyms: H II-204
Discovered in August 1784 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "pB, S, stellar, not verified."
Discovered by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "pB, vS, 4 arcseconds at the utmost in diameter, a good deal furry at the edges, and ? if not a little brighter in middle. It is not a 'stellar nebula', but rather a link between an anular and a globular; is probably a v distant and highly comp globular, has a star 9m 3' distant S.f.; night superb and vision perfect. This is one of the smallest if not the very smallest nebulous object I remember to have seen. It is a very remarkable object."
vB, vS, R, planetary nebula.
Knox Shaw, H. (1915) Note on the nebulae and star clusters shown on the Franklin-Adams plates. M.N.R.A.S., 76(2), 105-107.
Comments on papers by Harding (MNRAS, 74(8)), and Melotte (MemRAS 60(5)) describing objects foundon the Franklin-Adams plates; compares with plates taken with the Reynolds reflector (Helwan Obs Bull. 9-15):
Amongst the objects classed as globular clusters in the NGC, and not identified by Mr Melotte, 6629 is a planetary nebula.
Charlier, C V L (1931) "Stellar clusters and related celestial phaenomena", Lund Annals 2, 14, No. 19. Charlier examined prints from the Franklink-Adams atlas; "Table 6 gives a list of those objects in Bailey's catalogue for which the globular character is uncertain or not probable..."
NGC 6629 Remarks: "not found by Bailey."
The RNGC (Sulentic and Tifft 1973) notes that this is a 12.0 mag planetary nebula.
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "10.5M; 15" diameter; small, soft blob; 13.5M center star."
Houston notes that this somewhat challenging planetary can be seen as a nebula in a 10-inch, in which the disk appears gray and ill-defined.w
William P. Clarke (San Diego, California, USA) writes in the The Webb Society Nebulae and Clusters Section Report No. 10, July 1992: "Small, round and ill-defined. Central star easily seen. (21-inch f/20, x140, x350)."
Steve Coe, observing with a 13" f/5.6, notes: "Pretty bright, small and a little elongated at 220X. It is greenish and will reveal a central star with direct vision at 220X. It exhibits some of the "blinking effect"--the central star is much more prominent with averted vision than looking directly at it, so it will blink on and off as you look at the nebula then look away. This small planetary is about three times the size of the Airy disk on a night I rated 7/10 for seeing."
(PK9-5.1) Mag=11.3. Sagittarius: 18h, 25.7m; -23° 12' This is strictly a summertime object! As first sought at the end of August with the 'Teapot' dipping into the smoggy air just above the horizon, we did not detect it. Three days later we were lucky to catch it around midnight, when only about 30° above the distant Santa Cruz horizon. A nearly-round 16-arcsecond-diameter grayish or bluish disk, the planetary seemed fuzzy and non-stellar at 200x. It was discernible at only 50x: an oxygen-line filter darkened the background, and would help to reveal it in a sky suffering from severe photon pollution. In our 5th- magnitude naked- eye- limit sky, NGC-6629 was detectable without the filter.
In the online Southern Observer (article "The planetary nebulae of Sagittarius") this planetary is recorded as: "This 16" mag 11.3 grey disc is regularly round, diffuse at the edges and very slightly brighter toward the centre. The central star is mag 12.8 and therefore should be visible in my 25cm at high power, despite this I am yet to definitely detect it. To find: locate Lambda Sagittari, the mag 2 star marking the lid of the teapot. Move the scope 1 low power field W then 2-3 low power fields N and there it is. Be sure to check out M28, a mag 8 globular cluster adjacent to Lambda. RA 18.26 Dec -23.2. Winter."
The Messier objects
The Bennett objects
The Caldwell list
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