What is Interferometer?

• An interferometer consists of two or more separate telescopes that combine their signals almost as if they were coming from separate portions of a telescope as big as the two telescopes are apart.
  The resolution of an interferometer approaches that of a telescope of diameter equal to the largest separation between its individual elements (telescopes). However, not as many photons are collected by the interferometer as would be by a giant single telescope of that size.
  Some famous interferometers are
• the Very Large Array VLA
• the Very Long Baseline Array VLBA
• the Westerbork Synthesis Radio Telescope WSRT
• the Australia Telescope AT