[IAUC] CBET 1876: 20090716 : PN G75.5+1.7

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                                                  Electronic Telegram No. 1876
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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CBAT en CFA.HARVARD.EDU (science)
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PN G75.5+1.7
     Last July, D. M. Jurasevich, Mount Wilson Observatory, discovered and
reported that H-alpha CCD images taken on 2007 June 19.22 and 2008 July 6.17
UT, using an Astro-Physics 160EDF apochromatic refractor (+ SBIG STL-11000M
CCD camera + 6-nm Tru-Balance H-alpha filter) reveal a near-spherical shell
of gas, located within a faint H II region near NGC 6888, that was
apparently not noticed (or published) previously due to the density of stars
and gas in that area of Cygnus.  This shell appears as a slightly elongated
ellipse with its major axis at p.a. 5 deg and having an apparent size of
260" x 235"; its center is located at R.A. = 20h15m22s.2, Decl. = +38d02'58"
(equinox 2000.0); Jurasevich has posted photographs and other information
regarding this nebula at website URL http://tinyurl.com/ku4ppy.
     The nebula was independently noted and reported by K. B. Quattrocchi
(Clovis, CA, U.S.A.) and M. Helm (Fresno, CA, U.S.A.), who originally found
it on eight separate 10-min images taken on 2008 July 17.75 with a 40.6-cm
f/3.75 astrograph (+ FLI Microline 16803 CCD camera + H-alpha filter)
located at the Sierra Remote Observatories in the Sierra Nevada Mountains,
providing the position end figures of the nebula as 21s.5, 43"; they have
posted photographs and other information on this nebula at website URL
http://www.lostvalleyobservatory.com/page29crescentbubblenb/.
     A. Acker, Observatoire Astronomique Strasbourg, notes that the "INT
Photometric H-alpha Survey of the Northern Galactic Plane" (IPHAS; cf.
Gonzalez-Solares et al. 2008, ASP Conf. Ser. 394, 197; Gonzalez-Solares et
al. 2008, MNRAS 388, 89) lists an object a couple of degrees away at
R.A. = 20h15m22s.2, Decl. = +40d34'44".8.
     L. Kohoutek, University of Hamburg, writes that he can see PN G75.5+1.7
on both red and blue "transparencies" of the second Palomar Sky Survey (but
not on the first POSS photographs), noting that the nebula is extremely
faint there (only a trace), but having the same size as on the current
images.  Also, the blue star in the center is of similar brightness at all
epochs; this does not support a nova nebula, as the nebula has not changed
in about sixteen years.  Spectroscopy is encouraged, though this will be
difficult because of its faintness.


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                         (C) Copyright 2009 CBAT
2009 July 16                     (CBET 1876)              Daniel W. E. Green