Figure 1-11b (in the More section about the Michelson-Morley experiment) shows an eclipsing binary. Suppose the period of the motion is T and the binary is a distance L from Earth, where L is sufficiently large so that points A and B in Figure 1-11b are a half orbit apart. Consider the motion of one of the stars and 

(a) show that the star would appear to move from A to B in time T/2 + 2Lv/(c²-v²) and from B to A in time T/2-2Lv/(c²-v²), assuming classical velocity addition applies to light, that is, that emission theories of light were correct. 

(b) What rotational period would cause the star to appear to be at both A and B simultaneously?