So you have 2 telescopes a distance B apart looking at an area of sky at an angle theta. Then place a source at a small angle away from theta, alpha. Then I can show, using small angle approx for alpha the corolated output of the system is proportional to expi[k.B.alpha.cos(theta)]
Then average over a top-hat from -delta(V)/2 to delta(V)/2 (V=frequency) to give a sinc function
sinc[pi.B.alpha.cos(theta).delta(V)/c] so from this how do you
so if we know B how do we calculate the largest angular scale to which it is sensitive? Writing this may have answered my own Q is it when sinc gets to 0.5 or some thing and what is the value of alpha? Seems fine now but what would you put as delta(V)? Does this depend on the size of the actual individual telescopes? If so how? When does chromatic abberation become important?
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.