What is a Synthetic Optical Aperture Telescope? - http://www.mrao.cam.ac.uk/telesco...
"Although the principles of aperture synthesis have been known for many years, and are used regularly in radio astronomy, astronomers had thought that building an optical telescope using this principle was just too difficult. Light waves are about a million times shorter than radio waves, so the precision required in building such a telescope is a million times more challenging than for radio synthesis instruments." - Sanjeev Singh