From: Milton Aupperle <milton@outcastsoft.com>

Date: September 27, 2010 11:49:35 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Hoping to get a baseline for post-processing


Hi Tim;


On 25-Sep-10, at 3:12 PM, centurion40tim wrote:


Jim and others:


Since no one else chimed in, I'll take a stab at it.


It's been a while since I've shot a planet. I dusted off my old iMac and dug out my Unibrain. It was great to get out and shoot Jupiter again. The only problem was seeing was terrible. I believe I have the data I need, however, to get a decent pic out of these sets. Each set is about 4000 frames. Need a little help with AstroII DC's post processing tools. Specifically I need a baseline from which to proceed and/or any advice I can get:

a) I used both horizontal and vertical areas for fine alignment. Right?


I normally hand pick a area manually if there is any detail to be seen. From what you said about seeing being bad, it likely will make little difference.


b) What size area for comparison should I start with?


That depend son what Focal length you shot it at and if your scaling frames, but likely 64x64 for Jupiter at 2 to 3 meter focal lengths. If you used a long focal length where the limb is basically straight, then you need to use a bigger area to include some curvature to make the area "Unique".  See page 54 of the Astro IIDC manually for some explanation on what I'm talking about.


c) To what degree would the matching be when comparing pixels?


As long as you did not crank the crap out of the gains / brightness to add a lot of image noise 8 to 10 is usually a good choice.


d) Should I scale frames?


That has to be decided on a case by case basis. I normally use that to suppress noise and provide better alignment.


If you do use it, don't forget to increase the Pixel Area size comparison appropriately too.


e) Should I use Gaussian blur for estimation before stacking


Only use it if you have a lot of noise in the image from high gains.


f) Should I sharpen frames before I stack?


Since you mentioned it was a really bad turbulence night, probably not. There is likely nothing "sharp" to sharpen.


HTH..


Milton Aupperle