Interferometric telescopes History of the telescope

in 1868, fizeau noted purpose of arrangement of mirrors or glass lenses in conventional telescope provide approximation fourier transform of optical wave field entering telescope. mathematical transformation understood , performed mathematically on paper, noted using array of small instruments possible measure diameter of star same precision single telescope large whole array— technique later became known astronomical interferometry. not until 1891 albert a. michelson used technique measurement of astronomical angular diameters: diameters of jupiter s satellites (michelson 1891). thirty years later, direct interferometric measurement of stellar diameter realized michelson & francis g. pease (1921) applied 20 ft (6.1 m) interferometer mounted on 100 inch hooker telescope on mount wilson.

the next major development came in 1946 when ryle , vonberg (ryle , vonberg 1946) located number of new cosmic radio sources constructing radio analogue of michelson interferometer. signals 2 radio antennas added electronically produce interference. ryle , vonberg s telescope used rotation of earth scan sky in 1 dimension. development of larger arrays , of computers rapidly perform necessary fourier transforms, first aperture synthesis imaging instruments developed obtain high resolution images without need of giant parabolic reflector perform fourier transform. technique used in radio astronomy observations. radio astronomers developed mathematical methods perform aperture synthesis fourier imaging using larger arrays of telescopes —often spread across more 1 continent. in 1980s, aperture synthesis technique extended visible light infrared astronomy, providing first high resolution optical , infrared images of nearby stars.

in 1995 imaging technique demonstrated on array of separate optical telescopes first time, allowing further improvement in resolution, , allowing higher resolution imaging of stellar surfaces. same techniques have been applied @ number of other astronomical telescope arrays including: navy prototype optical interferometer, chara array, , iota array. detailed description of development of astronomical optical interferometry can found here [1].

in 2008, max tegmark , matias zaldarriaga proposed fast fourier transform telescope design in lenses , mirrors dispensed altogether when computers become fast enough perform necessary transforms.