How do you work out the largest angular scale to which it is sensitive

How do you work out the largest angular scale to which it is sensitive and the field-of-view and what frequency range it can be used?

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?

Redbelly98
Staff Emeritus