An Aragoscope is a telescope design based on diffraction around the edge of an occluding disc, named after French scientist
François Arago
Dominique François Jean Arago ( ca, Domènec Francesc Joan Aragó), known simply as François Arago (; Catalan: ''Francesc Aragó'', ; 26 February 17862 October 1853), was a French mathematician, physicist, astronomer, freemason, supporter of t ...
.
Concept
The light diffracted around the edge of a perfectly circular occluder interferes constructively at the central axis, and the resolution at that point would be equal to the resolution of conventional lens with the same size of the occluder. Only light intensity would be lower. On this basis it would be possible to create a telescope by placing a suitable disc in space accompanied by a separate telescope some distance away along its axis. This concept has been explored by NASA and received Phase One funding in June 2014 by the
NASA Innovative Advanced Concepts
The NASA Institute for Advanced Concepts (NIAC) is a NASA program for development of far reaching, long term advanced concepts by "creating breakthroughs, radically better or entirely new aerospace concepts". The program operated under the name N ...
(NIAC) program.
It is important to note that this is a very different approach from that taken by another NASA project, the
New Worlds Mission
The New Worlds Mission is a proposed project comprising a large occulter flying in formation with a space telescope designed to block the light of nearby stars in order to observe their orbiting exoplanets. The observations could be taken with ...
, which aims to use an occluder with "petals", otherwise known as a starshade, specifically designed to ''avoid'' diffraction onto the central axis.
See also
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Zone plate
A zone plate is a device used to focus light or other things exhibiting wave character.G. W. Webb, I. V. Minin and O. V. Minin, “Variable Reference Phase in Diffractive Antennas”, ''IEEE Antennas and Propagation Magazine'', vol. 53, no. 2, ...
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Arago telescope
Arago telescope (''Lunette Arago'') is a 38 cm (15 inch) aperture refracting telescope at Paris Observatory, installed in 1857. Francois Arago ordered this telescope from the telescope making firm Lebreours in 1839, and after a protracte ...
, a 38 cm (15 inch) refractor at Paris Observatory's east tower
References
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Telescopes