#25898 Sep 5, 2006
Sorry for the cross posting, it just seems that the "DL" part of the
Maxim groups is a bit busier. I just wanted to share my latest
progress I've made.
Friday night I took a whole bunch of images of NGC 7331 and also
managed to get most of them without too much drift from the RA of my
scope. I set my guide camera at 2.5 second exposures rather than the
5 seconds I've been using before. I got some advice that a longer
exposure would minimize the scope from autoguiding on the atmosphere -
which make sense - but then when I got one of those ugly 1.8 pixel
offsets, I'd have to sit there for 5 seconds before it would try to
correct for that. So, there are times that 5 seconds is good and
others when 3 or less is better. I stacked 16 images of the galaxy
group and came out with this as the raw stacked final version --
There is some vignetting in the image, some blue color around the
middle, and a couple of dust bunnies. Easy to fix. Here is the final
result after fooling with Photoshop for a long time..
Ok, this brings up anothe question. When I'm doing the RGB
conversion, I think I've got the red and blue possibly screwed up? I
am using an unmodified Canon 10D, so the red channel will ususally be
weaker, and more blue would show up. Now I get the opposite, red is
very strong, and blue is very weak. I did turn down the red channel
from the recommended 225 setting (things seem VERY red when I set that
to 225). I'm sure that is my problem, and I may be feeling
intimidated by the excess red in the raw stacked frame before I save
it as a .tiff. Then again, for some reason the blue is weak - which
is usually the dominant color with my camera, but I still end up with
a very strong red channel.
I do have a lot of light pollution in my area, so I'm sure I'm picking
up a lot of the familiar pink stuff. I'm guessing that I would need
to stray from the recommneded 10D RGB settings?
....but just how much, that is the problem.
Slowly getting there!