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RA: 19h 18m 28.08s
Dec: +06° 32′ 19.3″
Ch: MSA:1269, U2:206, SA:16
Type: planetary nebula
Mag: B=?, V=?
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NGC 6781. The position is for a very faint, very blue star -- the southeastern of two -- near the geometric center of the planetary. The star is not seen at all in any of the 2MASS images, but is clear on the DSS2B image.
Synonyms: H III-743
Discovered in 1788 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "cF, iR, resolvable, 3' or 4' diameter."
Sketched and described.
In the 5th edition of Webb's Celestial Objects for Common Telescopes it is described as "large round faint nebula, John Herschel calls it a planetary, E. of Rosse calls it a ring or spiral."
This 12th magnitude planetary nebula is described in the NGC as "faint, large, round, very suddenly brighter in the middle to a disc, a small star is N.f."
Burnham, S. W. () "Measures of planetary nebulae with the 36-inch equatorial of the Lick Observatory", Pub. Lick Obs., vol 2, p159-167. "The primary star is not central, but is north of the middle."
Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part I. M.N.R.A.S., 35(5), 159.
Photo Index by Jim Lucyk: Sky&Tel. 8/84 p187, Astronomy mag. 2/79 p19, Astronomy mag. 8/86 p86, Deep Sky #3 Su83 p23, Deep Sky #6 Sp84 p10, Astronomy mag. 7/87 p86, Burnhams V1 p231, Burnhams V2 p1174, Deep Sky #20 Fa87 p10, Sky&Tel. 9/87 p239.
The RNGC (Sulentic and Tifft 1973) notes that this is a 12.5 mag planetary nebula.
(IAAC) Obj: NGC 6781 - Inst: 12.5" f5 Dob
Observer: Scott Hogsten
Your skills: Intermediate (some years)
Date/time of observation: Aug 20,1998 00:15 EDT
Location of site: McConnelsville, Ohio (Lat 39N, Elev )
Site classification: Rural
Sky darkness: 6.5 Limiting magnitude
Seeing: 8 1-10 Seeing Scale (10 best)
Moon presence: None - moon not in sky
Instrument: 12.5" f5 Dob
Magnification: 125x, 150x
Object(s): NGC 6781
Category: Planetary nebula.
Data: mag 11.8 size 111"x109"
Position: RA 19:18.5 DEC +06:32
Large Faint nebula no exhibiting any real structure. I found this nebula to be relatively easy to find despite its low surface brightness. There was a slight hint of more structure on one side of this nebula than the other
Hartung notes: "In a field sprinkled with stars is a large faint grey object about 2' across of even illumination . . 15cm is needed for it."
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "12M; 2' diameter; large, faint and round; averted vision shows center void; high-x and N-filter shows S hemisphere brighter and crisper; 25' due E of bright star (6.5M) SAO 124457."
"This fine planetary nebula is relatively bright and large, being about 2' in diameter. This grey puffball of light is reminiscent of the Owl Nebula in Ursa Major. The southern portion of the nebula is slightly brighter than the northern portion, and I saw no central star."
Houston notes that this 12th mag planetary, about 2' across, was seen by him "without a doubt" in a 4-inch refractor.
Steve Coe, using a 13" f/5.6, notes: "Bright, Large, somewhat elongated at 100X. It is immediately obvious without the UHC filter. This planetary is shaped like the gibbous moon with the south side brighter in an arc. There is one star involved that stands out very nicely. The UHC filter helps some. I estimate its' size at one arc minute. 6" f/6 Dugas 7/10 22mm EP easy to see, going to 8.8mm it is faint, round, not brighter in the middle, pretty large, one star involved and it comes and goes, brighter on the east side."
Sanford notes that this planetary has a "large, very dim disk" and is easily visible in an 8-inch telescope.
DSM 3:23: * in W edge not vis.
15cm - annulus w/* inv. Roof.
- vis @ 62x. 190x shows 1'.5 circ spot. BS, 3Sep1981, Anderson Mesa.
25cm - 235x: m13 * on NE edge. 90" diam, S side brtr. dk patch on SW. two m14 *s inv. Roof.
- well-def perimeter. just off NE edge is m14 *. neb fades from S to N as though a wedge-shaped disk. sl annularity just N of geom center. BS, 3 Sep1981, Anderson Mesa.
30cm - fairly br annulus. m12 * on NE edge, m12.5 * in neb on W. 1'.6 diam, 40" hole. CBL, Roof.
16-inch f/10 SCT (127x 290x 462x)
High power is needed to observe it in full. A nebular filter made it a perfect globe of frosted light with a relatively easy magnitude 12 star on the north-eastern edge of the planetary. The south-western side is much more edges whereas the north-eastern side is washed away in the field of view.
22 August 1998, Farm site, Meade 8" with a 18mm wide angle & 26mm Plossl, 36' fov, Sky Conditions: Clear 7 to 8 magnitude
Soft, roundish to square glow, very large and a faint star in the middle. Some darker nebulosity and a bright star to the north following. Sting of stars to the north running away from this planetary nebula.
The Messier objects
The Bennett objects
The Caldwell list
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