From: "Duane" <macastronomer@mac.com>

Date: December 6, 2007 12:28:47 AM MST

To: Astro_IIDC@yahoogroups.com

Subject: The sharpness curve

Just got in from a session. That 300mb chart said it would be pretty stable tonight... NOT!

Oh well, I took some shots and froze my fingers off. It was -4 F and I'm just glad all the 

equipment worked.

Tonight's session leads me to a question. I always have AIIDC set to show me the graph 

after it determines sharpness. Most of the time this chart looks like a standard bell curve 

with room on either side. I've had it do other things (rarely) like put a block of images on 

the far left and a stream of images running off to the right, dribbling off at the end. This 

was a night of better seeing.

In any case, does this graph ever give a hint as to how good the seeing was by its shape 

and is there an ideal place to make the selection (% vs. #) of images to stack (such as, right 

where the images drop off dramatically or where there is a little plateau on the sharp side 

of the bell curve, or where there happens to be a large spike in numbers on the sharp 

side)?

Please let me know if you don't understand the question.

Thanks,

Duane