Many thanks to everyone answered my message

you might try w1ghz I believe he has some stuff(spreadsheet) to
calculate params for a cas.

Yep, I saw.


you might also look into optical design software a cas is the same
just the wavelength is longer in the one you are probably thinking of.

Could you explain which software do you mean? For optical design do you
mean optical cas telescope or optical geometry approximation?

Thank you again!

Emanuele Colucci