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(IAAC) Obj: ngc 6826 (Blinking Planetary) - Inst: 20" f/5 dob newt




Observer: Lew Gramer
Your skills: Intermediate
Date and UT of Observation: 1997-07-5/6, 04:15 UT
Location: Savoy, MA, USA (42N, elev 700m)
Site classification: rural
Limiting magnitude: 7.3 (zenith)
Seeing: 3 of 10 - pretty good
Moon up: no
Instrument: 20" f/5 Tectron truss-tube dob Newtonian reflector
Magnification: 70x, 420x
Filters used: None, UHC, OIII
Object: ngc 6826 (Blinking Planetary)
Category: Planetary Nebula [3a+2]
Constellation: Cyg
Data: mag 9.8  size 27"x24"
RA/DE: 19h14m  +50o32m
Description:
Flaunting itself as a well-defined little blob of sea-green haze
at 70x, this little planetary showed it's delightful "blinking"
behavior without any trouble - i.e., use of direct vision made the
central star pop out and the nebula become indistinct, while using
averted vision made the nebula suddenly prominent and the central
star "disappear" amid the green glow. But surprisingly, shooting
up to 420x made the view suddenly quite STEADY - in other words,
the central star and the bright core of the planetary both became
easily visible TOGETHER in direct vision. At this power, no annul-
arity (central darkening) could be perceived in the nebulosity.
Strange to tell, using a UHC filter at 420x, the nebula actually
began to "blink" again! This attenuation of the nebula vs. the
central star was unexpected(!), but no additional detail was seen.
Finally, using the OIII filter at this high mag, the central star
became complete lost in fairly solid nebulosity, being only inter-
mittently visible to direct vision 1 second in every 5 or so. With
an OIII, patches of the wide (2') outer halo of this planetary were
clearly seen,and the central core of the nebula showed a slight E-W
elongation. Neither of these features were apparent without the OIII.