Since nobody else has responded, I'll answer with what little I know.
It sounds perhaps like you are describing a Michelson stellar interferometer. It has been many years since I read the details of how these work, and only remember that it involves an interference measurement using two telescopes some distance apart, and assuming some form for the source intensity (eg., uniform disk or top-hat in the case of a star).
You could try a google search on "Michelson stellar interferometer". Unfortunately wikipedia does not give any details.
Regards,
Mark