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==Origin==
[http://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English], from Anglo-French ''arraier'', from Vulgar Latin ''arredare'', from [[Latin]] ''ad''- + ''a'' base of Germanic origin; akin to Gothic ''garaiths'' arranged
*[http://en.wikipedia.org/wiki/14th_century 14th Century]
==Definitions==
*1: to dress or decorate especially in splendid or impressive [[attire]] : adorn <he had already arrayed himself in his best clothes — Thomas Hardy>
*2a : to set or place in [[order]] : draw up, marshal <the forces arrayed against us>
:b : to set or set forth in order (as a [[jury]]) for the [[trial]] of a cause
*3: to arrange or display in or as if in an array <the … data are arrayed in [[descending]] order — Ed Burnett>
==Description==
An ''[http://en.wikipedia.org/wiki/Astronomical_interferometer astronomical interferometer]'' is an '''array''' of [[telescopes]] or mirror segments [[acting]] [[together]] to probe [[structures]] with higher [[resolution]] by means of [http://en.wikipedia.org/wiki/Interferometry interferometry]. The benefit of the interferometer is that the [http://en.wikipedia.org/wiki/Angular_resolution angular resolution] of the instrument is nearly that of a telescope with the same [http://en.wikipedia.org/wiki/Aperture aperture] as a single large instrument [[encompassing]] all of the individual photon-collecting sub-components. The drawback is that it does not collect as many photons as a large instrument of that size. Thus it is mainly useful for fine [[resolution]] of the more [[luminous]] astronomical objects, such as close [http://en.wikipedia.org/wiki/Binary_star binary stars].
Astronomical interferometers are widely used for [http://en.wikipedia.org/wiki/Optical_astronomy optical astronomy], infrared astronomy, submillimetre astronomy and [http://en.wikipedia.org/wiki/Radio_astronomy radio astronomy]. [http://en.wikipedia.org/wiki/Aperture_synthesis Aperture synthesis] can be used to perform high-resolution imaging using astronomical interferometers. [http://en.wikipedia.org/wiki/Very_Long_Baseline_Interferometry Very Long Baseline Interferometry] uses a [[technique]] related to the closure [[phase]] to combine telescopes separated by thousands of kilometers to form a radio interferometer with the resolution which would be given by a single dish which was thousands of kilometers in diameter. At optical wavelengths, aperture synthesis allows the [http://en.wikipedia.org/wiki/Astronomical_seeing atmospheric seeing] resolution limit to be overcome, allowing the angular resolution to reach the [http://en.wikipedia.org/wiki/Diffraction diffraction] limit of the array.
Astronomical interferometers can produce higher-[[resolution]] astronomical images than any other type of [[telescope]]. At [[radio]] [[wavelengths]] [[image]] resolutions of a few micro-[http://en.wikipedia.org/wiki/Arcsecond arcseconds] have been obtained, and image resolutions of a fractional milliarcsecond have been [[achieved]] at visible and infrared wavelengths.
One simple layout of an astronomical interferometer is a parabolic arrangement of mirrors, giving a partially complete [http://en.wikipedia.org/wiki/Reflecting_telescope reflecting telescope] (with a "sparse" or "dilute" aperture). In fact the [http://en.wikipedia.org/wiki/Parabolic_reflector parabolic] arrangement of the mirrors is not important, as long as the optical path lengths from the astronomical object to the beam combiner or [[focus]] are the same as given by the parabolic case. Most existing arrays use a planar geometry instead, and [http://en.wikipedia.org/wiki/Hypertelescope#Labeyrie.27s_hypertelescope Labeyrie's hypertelescope] will use a spherical geometry, for example[http://en.wikipedia.org/wiki/Astronomical_interferometer]
[[Category: Astronomy]]
[[Category: General Reference]]
==Origin==
[http://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English], from Anglo-French ''arraier'', from Vulgar Latin ''arredare'', from [[Latin]] ''ad''- + ''a'' base of Germanic origin; akin to Gothic ''garaiths'' arranged
*[http://en.wikipedia.org/wiki/14th_century 14th Century]
==Definitions==
*1: to dress or decorate especially in splendid or impressive [[attire]] : adorn <he had already arrayed himself in his best clothes — Thomas Hardy>
*2a : to set or place in [[order]] : draw up, marshal <the forces arrayed against us>
:b : to set or set forth in order (as a [[jury]]) for the [[trial]] of a cause
*3: to arrange or display in or as if in an array <the … data are arrayed in [[descending]] order — Ed Burnett>
==Description==
An ''[http://en.wikipedia.org/wiki/Astronomical_interferometer astronomical interferometer]'' is an '''array''' of [[telescopes]] or mirror segments [[acting]] [[together]] to probe [[structures]] with higher [[resolution]] by means of [http://en.wikipedia.org/wiki/Interferometry interferometry]. The benefit of the interferometer is that the [http://en.wikipedia.org/wiki/Angular_resolution angular resolution] of the instrument is nearly that of a telescope with the same [http://en.wikipedia.org/wiki/Aperture aperture] as a single large instrument [[encompassing]] all of the individual photon-collecting sub-components. The drawback is that it does not collect as many photons as a large instrument of that size. Thus it is mainly useful for fine [[resolution]] of the more [[luminous]] astronomical objects, such as close [http://en.wikipedia.org/wiki/Binary_star binary stars].
Astronomical interferometers are widely used for [http://en.wikipedia.org/wiki/Optical_astronomy optical astronomy], infrared astronomy, submillimetre astronomy and [http://en.wikipedia.org/wiki/Radio_astronomy radio astronomy]. [http://en.wikipedia.org/wiki/Aperture_synthesis Aperture synthesis] can be used to perform high-resolution imaging using astronomical interferometers. [http://en.wikipedia.org/wiki/Very_Long_Baseline_Interferometry Very Long Baseline Interferometry] uses a [[technique]] related to the closure [[phase]] to combine telescopes separated by thousands of kilometers to form a radio interferometer with the resolution which would be given by a single dish which was thousands of kilometers in diameter. At optical wavelengths, aperture synthesis allows the [http://en.wikipedia.org/wiki/Astronomical_seeing atmospheric seeing] resolution limit to be overcome, allowing the angular resolution to reach the [http://en.wikipedia.org/wiki/Diffraction diffraction] limit of the array.
Astronomical interferometers can produce higher-[[resolution]] astronomical images than any other type of [[telescope]]. At [[radio]] [[wavelengths]] [[image]] resolutions of a few micro-[http://en.wikipedia.org/wiki/Arcsecond arcseconds] have been obtained, and image resolutions of a fractional milliarcsecond have been [[achieved]] at visible and infrared wavelengths.
One simple layout of an astronomical interferometer is a parabolic arrangement of mirrors, giving a partially complete [http://en.wikipedia.org/wiki/Reflecting_telescope reflecting telescope] (with a "sparse" or "dilute" aperture). In fact the [http://en.wikipedia.org/wiki/Parabolic_reflector parabolic] arrangement of the mirrors is not important, as long as the optical path lengths from the astronomical object to the beam combiner or [[focus]] are the same as given by the parabolic case. Most existing arrays use a planar geometry instead, and [http://en.wikipedia.org/wiki/Hypertelescope#Labeyrie.27s_hypertelescope Labeyrie's hypertelescope] will use a spherical geometry, for example[http://en.wikipedia.org/wiki/Astronomical_interferometer]
[[Category: Astronomy]]
[[Category: General Reference]]