RE: [APML] A couple of E200 piggyback shots

Hey Andy, where in VA are you? I'm in Thaxton, about 1/2 way between Roanoke and Lynchburg.

Gary

www.starryestateobservatory.com

----- Original Message -----

From: Andrew Clegg

To: Discussion of Film Astrophotography

Sent: Saturday, October 23, 2004 10:07 PM

Subject: RE: [APML] A couple of E200 piggyback shots

Thanks to everyone for all their useful comments. That was exactly what I
was hoping to get. I learned the following things:

1) Most people don't like the tube shadow. I kind of like it, because it
gives depth, but I think I'll move the piggyback bracket up to the front of
the tube and let the depth be given by trees or other natural objects.

2) I should stop my lenses down a little to help with the vignetting and the
aberrations. Some of the aberrations in these pictures are due to a small
amount of field rotation, so I need to be more careful lining up my guide
star, the 'scope axis, and the camera axis.

3) I should correct for vignetting in post-processing when necessary. I have
run the images through the Background Subtraction program, and have posted
both before and after versions (http://www.w4je.com/ap0409.htm). I need to
do a little color balancing on the after, as the neutral gray background
isn't quite as pleasing as a slightly warmer background, in my opinion.

4) I do have the Pentax 6x7 200mm lens, but my first attempt with this lens
(M31) suffered from too much field rotation (too much for me to even think
of posting!). Again, I need to be much more careful on the alignment of the
'scope and camera.

Thanks again to everyone--I've learned more from this forum than all other
sources combined.

And I'll be posting more analog photos if the weather here in Virginia ever
clears up. For now, I'll be getting my digital point-and-shoot and my Orion
ED-80 ready for Wednesday night.

Thanks again to all!

Andy

http://www.w4je.com/ap0409.htm

_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo