Cat's Eye Nebula + IC 4677
Bernd Nies
I have a question:
West of the famous Cat's Eye Nebula is the small Object
IC 4677, listed in Dreyer's Index Catalogue. It is also
noted as MCG 11-22-17 in the Morphological Galaxies and
as PGC 61193 in the Principal Galaxies Catalogue.
According to these three catalogues this object should
be a galaxy.
But refer to the attached POSS image: The galaxy in
the left part is NGC 6552 and the bright 'star' in the
right part is the Cat's Eye Nebula NGC 6543. The bright
nebula is surrounded by a faint halo which diameter is
approximately 350 arcseconds. The probable 'galaxy'
IC 4677 is located inside this halo. This object doesn't
look like a galaxy but more like a bright gaseous knot
in the halo - maybe an ancient outburst of the central
star. There are several smaller and fainter knots in
the halo.
Neither the halo nor IC 4677 are visible with an
12.5 inch newtonian with O-III or H-beta filter.
Does anybody know more about IC 4677? I need this
information for our Deep-Sky Corner which you will find
under the URL below.
Regards ...
Bernd
__________________________________________________________
Bernd Nies | Phone/Fax: +41-[call if needed]
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Per Amund Amundsen
In article <324641...@itr.ch> Bernd Nies <bn...@itr.ch> writes
[ Question of the nature of IC 4677, located inside the extended halo
of the Cat's Eye nebula, NGC 6543]
According to the Simbad database, IC 4677 is indeed a part of the Cat's Eye,
and not a galaxy. Your interpretation as a remanent of an ancient
outburst of the central star is thus quite possibly right. The visual
magnitude is given as 15m.
per a
--
Per Amund Amundsen per...@hsr.no
School of Science and Technology, Fax: (+47) 51831750
Stavanger College Tlf: (+47) 51831877
PO Box 2557 Ullandhaug, N-4004 Stavanger, Norway
Bob Luffel
: In article <324641...@itr.ch> Bernd Nies <bn...@itr.ch> writes
: [ Question of the nature of IC 4677, located inside the extended halo
: of the Cat's Eye nebula, NGC 6543]
: According to the Simbad database, IC 4677 is indeed a part of the Cat's Eye,
: and not a galaxy. Your interpretation as a remanent of an ancient
: outburst of the central star is thus quite possibly right. The visual
: magnitude is given as 15m.
My observations of this agree. In August I was observing through a 25", and
checked the knot with and without an OIII filter. The knot was still very
visible in the OIII, something I wouldn't expect from a galaxy.
Bob
Bernd Nies
Per Amund Amundsen wrote:
> According to the Simbad database, IC 4677 is indeed a part
> of the Cat's Eye, and not a galaxy. Your interpretation as
> a remanent of an ancient outburst of the central star is thus
> quite possibly right. The visual magnitude is given as 15m.
Bob Luffel wrote:
> My observations of this agree. In August I was observing
> through a 25", and checked the knot with and without an OIII
> filter. The knot was still very visible in the OIII, something
> I wouldn't expect from a galaxy.
Thank you both for this helpful information. I'll mention
it in our Deep-Sky Corner at astro!nfo. 25 Inches aperture
is indeed brighter than 12.5.
But there are some galaxies which are still visible with
an O-III filter and also an H-beta filter. M 33 is a good
example. In M33's 'Orion Nebula' NGC 604 structures can be
seen. Exciting to see extragalactic deep-sky objects.
Clear Skies!