When I moved from DSLR to CCD imaging, I found that I had issues regarding how to calculate the correct exposure depending on sky conditions. I found on the net a link describing the mathematics behind calculating the sky fog limit, therefore I decided to translate it into a small application to keep with me in the field when I start my imaging session. The program runs on a DOS window. An improved Windows-based commercial version (Perfect Exposure) is available for a small fee and it allows to calculate the right time also for DSLRs.
How does it work?
Take an exposure of, let's say, 5 minutes
Open your favourite processing program and find out the average/median ADU value for the background
Get from your CCD specs the values for the Gain and ReadOut Noise
Run the program and input the above values, where requested
CCDCalc will output the estimated correct exposure time
This software was developed because some amateur astronomers felt the need for it. If you appreciate my effort please consider donating. You may do so by Paypal or by direct transfer to my bank account.
What do you get from donating?
Your name will be listed in the Donors Page and your website will be listed. Moreover, as a donor, your request for new features will be considered as higher priority with respect to other feature requests