(IAAC) Obj: IC 4593 (blinking planetary) - Inst: 13" f/5.6 Newt

[These "blinking pn" logs are from Steve Coe's posts to our 
Announce list last July. This one's in the evening sky now! -Lew]
Observer: Steve Coe
Your skills: Advanced (many years)
Date/time of observation: Spring
Location of site: Arizona USA
Site classification: Rural
Transparency: 6 and 8 <1-10 Transparency Scale (10 best)>
Seeing: 5 and 7 <1-10 Seeing Scale (10 best)>
Moon presence: None - moon not in sky
Instrument: 13" f/5.6 Newt
Magnification: 100x, 165x, 220x, 440x
Filter(s): None.
Object(s): IC 4593 (blinking planetary)
Category: Planetary nebula.
Class: 2+2
Constellation: Her
Data: mag 10.9 11.13m*; size 12"x10" (halo 120")
Position: 161144 +120417
Lew, here is a "blinking planetary" in Hercules:
IC 4593  faint, small, little elongated, stellar nucleus. Greenish
at all powers, central star most obvious at 165X. This planetary
"blinks", look at it, then use averted vision and the nebulosity
will appear and disappear. Sun Valley Parkway Seeing 5/10,
transparency 6/10, easy at 150X, but needs power.  220X Pretty faint,
small, very little elongated 1.2 X 1 in PA 90, central star is
obvious. This planetary has been called the "while-eyed pea" and I
see why, the nebula is light green and the star is as white as Spica.
Averted vision makes it grow about twice its size and there is some
very faint outer nebulosity seen.
IC 4593 Cherry Rd. S=7, T=8, 13"  100X-just recognized as a disk,
pretty faint, very small, round, stellar nucleus; averted vision
makes the disk grow three times what it is with direct vision.
220X brings out the central star.  440X is the best view, round
light green disk with white central star.
Steve Coe
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