Hi Joe, On 26 Jun 2010, at 11:23, Joe Bauman wrote:
Hi Patrick, I use an SBIG ST-402ME. I don't know where to find those numbers. Are they part of the info that is recorded with the image? Thanks again, Joe
Looking through the owners manual for the 402 I see: Non-ABG CCDs 100,000 electrons ABG CCDs 50,000 electrons But, just to throw a fly in the ointment, while looking elsewhere on the SBIG site I found this statement: "Since the same flat field is added to itself a number of times, be sure that you do not saturate the flat field image by starting with pixel values too high. Typically try to keep the pixel values between 10% to 20% of saturation for this purpose. For single flat field images, try to keep the values to approximately 50% of saturation." If I'm reading that right it would seem to indicate that one goes for 50% of saturation only if doing a single flat field. For multiple flat fields (which I'm pretty sure most everyone recommends) to be combined into a master flat that should only be 10 to 20 percent. So at this point I think I'll bow out and wait for more knowledgeable folks like Jerry and Tyler to chime in and set me straight. Sorry for the confusion, patrick