ASTRO: NGC 7023 Iris Nebula

Thanks to two huge red pine (over 100' tall) that block snow from piling
up on my observatory roof I've got a blind spot near the pole. This
object is only out of the trees for about a half hour out of each 24
hours. So taking it was a real chore. Add clouds every time and it
took me 18 nights over 3 months. Then I found a problem I hadn't
counted on. The warmest night I recall was 10C. I know the coldest was
about -31C. That 40C temp difference shows up as a image size
difference! Those taken at the coldest temps are larger than those at
the warmest. I'd have thought it the other way around. CCDSoft refused
to align them. AIM did align them without complaint, just didn't tell
me it didn't work. Since I was processing the center of the image I
didn't notice the problem until I was about done. I tried to match it
using Photoshop to resize the images but my attempts all failed worse
than going without correction. Anyone know if Registar or any other
such aligning program resizes slightly. From my attempts in Photoshop
it appears the size change isn't linear, the right side enlarged more
than the left so just resizing doesn't work, they need resizing that is
different for different parts of the image! Either that or I don't
image over a 40C temperature range. While the times look long, these
were nearly all taken with clouds so the total light is far less than
the times would indicate. I used every frame I could get my hands on.
It has now moved where it is in the trees all evening so I have to wait
until the small window opens next fall to retry it.

14" LX200R@F/10, L=57x5' R=12x5', GB=11x5' each all binned 2x2,
STL-11000M, Paramount ME

Rick
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Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".