Does software exist, preferably downloadable from the Internet, that I can use to analyze original optical designs of telescopes?
Yes. The easiest way to find what’s out there is with a fine-tuned Google search. Right now, if you enter “optical design software” as the search terms, you get a few million Web pages. But near the top of the hit list you'll find Northern Lights Optical’s convenient tally of such software at www.minerals.sk.ca/atm_design/links.html. The software options range from free demonstration versions to powerful commercial applications.
— Stuart J. Goldman