Main Question or Discussion Point
You can get the idea of the size of an object by knowing the distance to the object and the angular distance between the object's edges. Obviously, this is an intuative part of human vision. We can use this method to measure the diameter of our own star. We have methods to measure the distance to stars rather accuratly. Do we have the angular resolution within telescopes to make an accurate measurement of any stars diameters? Is there there any other method to make such a measurement?