(IAAC) Obj: Abell 86 - Inst: 18" f/4.5 Dob

[anonymous at sedna.atmob.org]

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

Observer: John Tatarchuk
Your skills: Advanced (many years)
Date/time of observation: 12/16/06, 12/17/06, 12/20/06
Location of site: Davis Mountains, 10 miles west of Fort Davis, TX (Lat , Elev 6000')
Site classification: Rural
Sky darkness: 10 <1-10 Scale (10 best)>
Seeing:  <1-10 Seeing Scale (10 best)>
Moon presence: None - moon not in sky
Instrument: 18" f/4.5 Dob
Magnification: 110X, 230X
Filter(s): OIII
Object(s): Abell 86
Category: Planetary nebula.
Class: 
Constellation: Cepheus
Data: mag 16.7p  size 70"
Position: RA 0h:1.5m  DEC +70:43'
Description:
(Probable observation)- this one was so close to a positive observation I
tried to confirm my sighting on 12/16, 12/17 and 12/20. This planetary is one
of the more difficult Abells. It comes in as magnitude 16.7p and 70” across.
After matching the Cepheus star field with the Aladin Previewer finder chart I
made, I was able to acquire an extremely faint, perhaps circular glow on the
threshold of perception using 110X and 230X and OIII filtration. A flattened
quadrilateral of stars just to west aided in identification of the correct
field and image scale. Unfortunately, there were a few very faint stars near
the nebula’s location that in extreme adverted vision “clouded” the view too
much to know whether I was perceiving the combined glow of a star or two, or
the actual nebula. Reverting to semi-adverted vision for better resolution
unfortunately made the nebula impossible to acquire, and even when using full
adverted vision, the nebula was not able to be reacquired easily.
On the third night I tried to observe this object, I went so far as to say I
am 99% confident I saw it. After studying the star field at length, I was able
to be almost sure the faint glow I was repeatedly spotting near the position
was the nebula and not a pairing of two of the nearby 15th and 16th magnitude
stars. Even though Abell 86 has decent separation between it and any wide star
pairs you might confuse it with in adverted vision, it’s really tough to
determine the exact location of faint circular glow you only see popping into
adverted vision every 30 seconds against a background of 15th magnitude stars
at 230X with OIII filtration in a telescope without tracking. So in the end, I
will have to rate this as a highly promising- but negative- observation. I
almost surely saw it, but I have been fooled before.

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