Fig1_7 Interferometer

Fig1_7 Interferometer

Fig. 1.7 . When incoming radiation approaches the Earth at an angle, the crests of the radiation will arrive at two separated telescopes at slightly different times. This delay in arrival time is the distance X divided by the speed of light. If X is an exact multiple of the wavelength, then the waves detected at the two telescopes will be in phase and add up when combined. If not, they will be out of phase and interfere. The angular resolution of such an interferometer, or interference meter, is equal to the wavelength divided by the effective baseline. When the object being observed is directly overhead, the effective baseline is equal to the distance between the two telescopes.

Copyright 2010, Professor Kenneth R. Lang, Tufts University