From: Willie Strickland <cwskas@earthlink.net>

Date: August 27, 2009 12:56:19 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: gain vs frame rate

Generally speaking, would it be better to go with lower gain and settle for lower frame rate?  I have been trying to get the highest frame rate that I can and then adjusting the gain as needed.

For each filter, I increase the gain until I start to get saturated pixels and then back it off 50 or so units.  Then I click the Calc Avg Sharpness button, then I capture 600-800 frames.  I often grab 2 or 3 movies with each filter and always recalculate the average sharpness just before capturing.

As to the Sharpness value, is 2 better than 5 or vice versa?  I thought maybe the smaller the sharpness value, the better the focus and the smaller the range, the better the seeing.  But looking back at the movies, I am not sure.  I just reread the pages that discuss sharpness and didnt find a specific definition of sharpness value.

The example below is Jupiter with my DMK21AF04 on the .6m scope.  I usually do not get any moons in the frame unless they are quite close.

Willie Strickland

cwskas@earthlink.net

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

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.