From: Willie Strickland <cwskas@earthlink.net>

Date: August 27, 2009 5:38:15 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Re: confidence intervals & frame selection

Thanks for the response, Milton, and sorry for my delayed response.  I have been out at night quite a bit this week, but not gotten around to doing any processing.  When the skies are good, I try to get data.

I am really anxious to try my hand at some of the Jupiter frames I have captured.

Willie Strickland

cwskas@earthlink.net

On Aug 20, 2009, at 10:09 AM, milton_aupperle wrote:

Hi Willie;

You have a "Type B - Single unskewed symmetric hump", as described on page 41 of the Astro IIDC manual and I copied the relevant section out of the manual:

--------- Start Quote

Type B - Single unskewed symmetric hump with a narrow range of sharpness values and a  small STD96 value of probably 0.05 and lower,as shown below. This is the curve you get on good imaging nights or if you take lots of sample under consistent skies. With this you should select a Confidence Interval percentage that is to the right of the central hump in around the 50 to 75% range, depending on how many frames you want to use in your stack.

--------- End Quote

Your STD96 value is higher than I mention, but you also have a much higher sharpness value range than I typically see (I'm used to 1 or 2, your getting 5), so you can expect higher STD. You likely had Jupiter filling the image?

Your Brightness / Gains were fairly high (608 out of about 1024), so you likely need 100 to 300 frames to suppress the pixel noise, depending on how much sharpening you plan on doing after stacking.