(IAAC) Obj: NGC 6826 - Inst: 13" f/5.6 Newtonian on Bigfoot German EQ

Observer: Steve Coe
Your skills: Advanced (many years)
Date/time of observation: Aug 97
Location of site: Strawberry, Arizona USA (Lat +34, Elev 7000 ft)
Site classification: Rural
Sky darkness: 8 <1-10 Scale (10 best)>
Seeing: 6 <1-10 Seeing Scale (10 best)>
Moon presence: None - moon not in sky
Instrument:  13"  f/5.6 Newtonian on Bigfoot German EQ 
Magnification: 100X, 160X, 220X
Filter(s): none
Object(s): NGC 6826
Category: Planetary nebula.
Constellation: Cyg
Data: mag   size 
Position: RA :  DEC :
NGC 6826 is the Blinking Planetary.  This medium sized, 9th
magnitude planetary can be located at 100X.  It appears as a
non-stellar blob in the Milky Way.  I first saw the blinking effect
in an 8" scope at 200X.  If you look directly at the planetary the
central star is prominent compared to the greenish nebulosity.  Then
averted vision will make the nebula appear brighter and overwhelm
the star. Alternating between direct and averted vision will produce
a blinking on-then-off effect that is fascinating.  In the 17.5" the
effect is unmistakable.  There are several other planetary nebulae
that have the right central star to nebula brightness to show off
this effect.  
Using 13" f/5.6 on a excellent night at 7000 ft.
in Arizona, this planetary is bright, large, somewhat elongated
and greenish.  The central star is easy at 150X as it floats in
a rich Milky Way field of view.  On a 7/10 night, it is bright, 
pretty large, very little elongated 1.2 X 1 in PA 170 at 100X.  
It is easily found at 100X.  The central star is better seen 
at 220X, but the blinking effect is better at 100X, the 
central star "goes away" with averted vision.  The PN is 
light green at all powers.
Ultimate Star Party, McDonald Obs. Oct. 95, S=6, T=8, 25 in. f/5--
NGC 6826 (blinking planetary)  in 25" with 9mm;  "large" central star is
obvious.  The dark markings can be seen in the bright disk, they are about
60 percent of the way out from the core and are thin dark lines.  The
blinking effect does not happen very well at this aperture.  The large
central star is a stellar wind effect, so we are not seeing the
actual central star, but a bright annulus of gas surrounding it.
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