Possible
new Planetary Nebula in Sagitta near Sharpless 2-80
I made an
interesting discovery in July. I imaged Sh2-80 in two nights from the 5th
of July to the 7th of July and found an uncatalogued
possible Planetary Nebula nearby. The image is at
http://ccd-astronomy.de/temp8/Sh2-80/Sh2-80colourcropgut.jpg
The
possible new PN can be found near the lower left corner of the image, it is a
quite obvious small red ring near the brightest blueish
star in that corner.
Position is RA 19 12 10.365 DEC +16 46 36.47.
When looking for reference pictures the only picture that shows it was an image
by Rick Johnson which can be found at
http://www.spacebanter.com/attachment.php?attachmentid=2908&stc=1
All other
images either had a smaller field of view or did not have the required
resolution.
The nebula is not in SIMBAD. Here is a link to all objects known to SIMBAD
within 5 arcminutes:
http://simbad.u-strasbg.fr/simbad/sim-coo?CooDefinedFrames=none&Coord=19%2012%2010.365%20%20%2b16%2046%2036.&CooEpoch=2000&CooFrame=FK5&CooEqui=2000&Radius.unit=arcmin&submit=submit%20query&Radius=5
I have
searched for papers mentioning this nebula in
http://xxx.soton.ac.uk/find/astro-ph
with the keywords “planetary nebula sagitta”
without time limit and for “planetary nebula” since January 2010 and found no
reference to this object.
One might
wonder how such a bright object could have been overlooked so far, the answer
is that the POSS doesn't have the resolution to show it as a ring, it is only
visible as a slightly fuzzy star in the digitized sky survey:
http://stdatu.stsci.edu/cgi-bin/dss_search?v=poss2ukstu_red&r=19+12+10.365&d=%2B16+46+36.47&e=J2000&h=4&w=4&f=gif&c=none&fov=NONE&v3=
The
presence of this object in the picture of Rick Johnson and in the DSS proves
that the object is real. Still to be confirmed is its nature as a planetary
nebula and whether it is really “new” or has been discovered before e.g. by the
IPHAS Ha survey.
Judging by its appearance (which resembles the famous “ring nebula” M57) I
would expect it to be a Planetary Nebula as I know no other class of objects
that show such a shape.
Until
someone puts me right I will call this object “Lilge1” in expectance of the other
99 nebulae I might discover to (almost) match Messier’s
catalogue ;-)
The first
image linked in this page and the following ones were taken from my rooftop
terrace in the central part of Berlin with a 10” Meade ACF telescope with an AstroPhysics CCDT67 reducer and an Atik
383L+ camera, the image scale is 0,57”/pixel. Filter used were Baader Ha (7nm), [OIII] (7nm) and RGB. The first image is a
Ha:OIII:OIII combined with
an RGB. In the following links I will show the individual channels, all images
are calibrated (flat fielded and dark frame subtracted):
Ha (20x10
minutes):
http://ccd-astronomy.de/temp8/Sh2-80/Lilge1-Ha.jpg
[OIII] (unfortunately only 4x10 minutes as the main object Sh2-80 was
almost invisible in OIII)
http://ccd-astronomy.de/temp8/Sh2-80/Lilge1-OIII.jpg
For
comparison a Ha image with only 4x10 minutes, stretched similarly to [OIII]:
http://ccd-astronomy.de/temp8/Sh2-80/Lilge1-Ha4x10.jpg
These
pictures show that the nebula is visible in [OIII], but much better in Ha.
Finally
RGB, each a stack of 3x5 minute exposures:
Red:
http://ccd-astronomy.de/temp8/Sh2-80/Lilge1-red.jpg
Green:
http://ccd-astronomy.de/temp8/Sh2-80/Lilge1-green.jpg
Blue:
http://ccd-astronomy.de/temp8/Sh2-80/Lilge1-blue.jpg
I am not
sure if weather will permit me to do deeper [OIII] images and possibly
luminance to look for a central star, so any hints, images etc. are welcome.
You can
reach me at slilge@web.de
Stefan Lilge
