From: Alan Friedman <alan@greatarrow.com>

Date: November 28, 2005 3:22:36 PM MST

To: Astro_IIDC@yahoogroups.com

Subject: saturn from November 20th

Hi all -

I've uploaded a saturn image processed over Thanksgiving weekend from files captured with AstroIIDC on November 20th. I also included the luminance and RGB images used to create the image.

http://groups.yahoo.com/group/Astro_IIDC/files/Planetary/saturn112005.jpg

http://groups.yahoo.com/group/Astro_IIDC/files/Planetary/saturn112005parts.jpg

Saturn is still quite dim in my 10" mak at f32 with the RGB filters. To get a fairly bright signal I used a very long shutter (750ms R & G, 1 second B), capturing only 100 frames through each filter and stacking 50-60 of these for the image. As you can see, the RGB component only provides the color so the softness of the image is really of no consequence. (note that the color and luminosity images had further adjustments in the final composite.)

The luminance was created from four streams captured at 30 fps using the 10" at f45 using no filter. The seeing (about 4-5/10 Pickering) deformed the image quite severly even in the sharpest frames. I hand selected about 15% of the frames creating stacks of about 200 frames, did mild processing on each and then stacked the four resulting images and processing further. The selection and stacking was done in Keith's Image Stacker. The RGB image was compiled, enlarged and rotated to match the luminance image in Adobe Photoshop CS2.

Quite a bit of time was spent to make a only fair image. The processing values are pretty good, I think, but there is little fine detail that emerged through the seeing. Saturn is probably the least forgiving target for poor seeing requiring 6-7/10 or better for a sharp result. But I can't resist trying anyway.

best wishes -

Alan