(IAAC) Obj: Simeis 147, Sh2-240 - Inst: 18" f/4.5 dobsonian

**anonymous@sedna.atmob.org**

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Observation Poster: John Tatarchuk <tatarjj@auburn.edu>

Observer: John Tatarchuk
Your skills: Advanced (many years)
Date/time of observation: 11/21/06
Location of site: Conecuh National Forest, South Alabama (Lat , Elev )
Site classification: Rural
Sky darkness: 6.8+, Gegenschein visible <Limiting magnitude>
Seeing: N/A <1-10 Seeing Scale (10 best)>
Moon presence: None - moon not in sky
Instrument: 18" f/4.5 dobsonian
Magnification: 75X
Filter(s): OIII
Object(s): Simeis 147, Sh2-240
Category: Supernova remnant.
Class: 
Constellation: Taurus/Auriga
Data: mag --  size 4 degrees?
Position: RA 5h:40  DEC +28:
Description:
I'd been trying to spot this object since 2002.  All I could ever see was hints
of nebulosity around 5h 43m +28 25’, but even this was too faint for me to be
absolutely certain.  To assist me in spying this object and other faint
nebulae, I made some modifications to my scope to make it more light-tight and
added an anti-fogging system that allows me to observe under a hood without
fear of fogging the eyepiece.  With these modifications in place, I was in
good shape to finally spy Simeis 147 under the dark skies of Conecuh National
Forest.  Finally!!! I was at last able to make a positive observation of this 
object.  I was able to definitively pick out a nebulous signal at three 
locations in this huge nebula.  All observations made with 27mm Panoptic with 
OIII filtration.

Region 1:
Rapidly sweeping the scope across the region west of SAO 77322 and a triangle 
of magnitude 7 stars about 45' to the west, I was able to nearly imperceptably
pick up what appeared to a a faint filament running from just south of 
SAO 77322 and into the triangle of stars.  Filament only visible when scope 
was moving.  Not sure if I was a victim of adverted imagination on this region;
the brain can and will sometimes "connect" stars together to create the false
impression of a nebulous object.  This is the weakest of the three regions I 
was able to observe.

Region 2:
Picking a region where several filaments came together, I started sweeping the
scope across the area at 5h 45m +27 10, hoping to pick up the faint combined 
glow of these strands of nebulosity.  Indeed, I was able to pick up an 
incredibly faint increase in the sky background brightness in this area.  
Moving the scope around, I was able to follow this broad brightening and 
determine it to be about 2 degrees across in the NE-SW direction, about half a
degree wide at its widest, and kidney bean shaped.  It seemed to taper a bit 
on its southwestern end, terminating just south of SAO 77350.  To the 
northeast, the faint glow seemed to come to an end around 5h 46 +27 20’.  This
glow is only visible when scope is swept across region.

Region 3:
The last and "brightest" off all the regions of nebulosity I detected.  If it 
wasn't for this region, I might have considered the whole observation a 
negative one.  This is the region, 5h 43m +28 25’, where I had always thought 
I was detecting a faint nebulous signal.  Just to the east of this area, there
is a grouping of magnitude 9-10 stars that appear to form a very loose open 
cluster of sorts. Moving the scope across the region back and forth, I 
noticed that the "open cluster" definately seemed more nebulous that it had
ever been.  However, more importantly, I noticed that the nebulous glow I was
noticing in the region seemed offset to the west from the "open cluster",
just as the long exposure images show!  The region was definately brighter
than any other I had detected; later on, it even started to become visible in
adverted vision without having to move the scope at all.  Sweeping the scope
across this area seemed to even show that I might be starting to pick up a
filament running off this region to the north, but it could have just been a
very faint star chain playing tricks on my mind.

I am by no means done with this object, and plan to return to it and try to
spot more nebulous areas as soon as possible.  I'll see how much I can spy 
under the dark skies outside of Fort Davis, TX next month.
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