From: "doodlebun" <gbleser@bellsouth.net>

Date: July 22, 2008 8:36:04 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: double hump stacking histogram

Thanks Milton. You explained the behavior of the save-as confusion. 

Last night we were imaging Jupiter trying to catch the shadow transit 

when we ran into these issues:  1. Patches of scattered hazy clouds and 

streaks traversed Jupiter. Therefore the brightness of Jupiter was 

dimming on and off. When the movie was processed the resulting 

histogram wasn't the usual Gaussian curve but a double hump at 66% 

confidence level. In the portion to the left of the pointer (the images 

that wouldn't be used) a bell curve appeared. Then to the right of the 

confidence pointer there was another much lower hump, like a mesa. Is 

this behavior typical of imaging a source that doesn't maintain a 

constant level of brightness? Would you recommend setting the histogram 

setting in the capture mode to "Auto", which would tell the program to 

constantly bring the brightness of each frame to a specified level? Or 

would that just make things worse?