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(IAAC) Re: [Planetary_Nebulae] NGC 6826



Susan Delaney noted:
>>The blinking effect was noted with direct vision at all powers.
>
>When I listened to my tape a second time, I realized that I had stated
>this *before* using the barlowed 7.5mm. So it only applies to the
>other powers. This PN will have to be revisted!
>Has anyone seen this object blink at higher powers?
Sorry for the late reply on this one, Susan! Well, I can certainly
confirm that the blinking effect *is* dependent on magnification. I
would supplement what others have said, though, by noting that the
blinking CAN be clearly seen in at least a 20" scope in some cases:
  http://www.visualdeepsky.org/netastrocatalog/msg00238.html
  http://www.visualdeepsky.org/netastrocatalog/msg00362.html
(That second link also contains a fine explanation of the physiolo-
gical causes behind blinking, by the eloquent Mr. Nick Martin...)
On the other hand, here is an observation by the renowned Mr. Patrick
Maloney, where he actually FAILS to log any blinking with a 4.5" Newt!
  http://www.visualdeepsky.org/netastrocatalog/msg00949.html
I suspect that a great deal depends on the sky contrast at the time
in which your observation is made... And too, maybe there are other,
more intriguing reasons why the "blinking" seems to be on the blink
itself at times!? I'd love to hear more experienced observers' ideas...
Finally, I second Eric Honeycutt's note that there are a whole host of
planetaries in range of moderate and large amateur scopes, which will
very merrily "blink" with the right power and observing conditions. :)
Here are logs of three such objects, NGC 6629, IC 4593, and IC 418...
  http://www.visualdeepsky.org/netastrocatalog/msg01475.html
  http://www.visualdeepsky.org/netastrocatalog/msg01478.html
  http://www.visualdeepsky.org/netastrocatalog/msg02065.html
Clear skies,
Lew Gramer
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