[Shiraz (Ray)]

Hi
Mike has agreed to put the attached spreadsheet in the "how to" section. In the meantime, would be grateful for any feedback.

the spreadsheet essentially puts most of the theory in one place - you can enter your environment, target brightness, telescope and camera characteristics and desired imaging time. It will tell you:
your sampling/resolution,
the expected FWHM at the focal plane,
the field of view,
the overall SNR performance with different sub lengths,
the optimum sub length,
the effective well depth after stacking and
the ADU value that you should see in the sky background of a sub.

It is a protected excel spreadsheet, but it also runs under openoffice. Best to unzip and scan it first and excel will query if you want to use a web sourced spreadsheet, so you will probably need to enable editing to get it to work. It has no macros and has been zipped for attachment through IIS. I use a fully up-to-date win10 system with the Microsoft security suite.

I have used the spreadsheet for a number of years and it has been spot-on for the two systems I designed with it. It allows different systems to be compared or any "what if" changes to an existing system to be assessed - before spending any money. It started life as a luminance-only version, but now also provides a rough estimate of performance with RGB filters. It is not really suitable for narrowband (better than nothing though) - am working on a NB version. I have tried to put in instructions and explanatory notes - are they sufficient?

the two attachments are an image of part of the main screen and the spreadsheet itself.

regards Ray

edit: just fixed a very minor issue in one cell - thanks for feedback