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Adaptive optics schemes for future extremely large telescopes

Gontcharov, Alexander LU ; Owner-Petersen, Mette LU ; Andersen, Torben LU and Beckers, JM (2002) In Optical Engineering 41(5). p.1065-1072
Abstract
The adaptive optics for any telescope in the 25- to 100-m class will be complex. It is believed that adaptive optics should, to the maximum extent, be designed as an integrated part of a telescope. The proposed Swedish 50-m Extremely Large Telescope is considered here to illustrate the principle of integrated adaptive optics. Two alternative designs both using the Ritchey-Chretien telescope system and laser guide star (LGS) reference sources are presented. The first design employs trombone optics, which bring the laser guide star images back to the normal Ritchey-Chretien focal surface (referred to as the RC-focus) from the LGS focal surface (referred to as the LRC-focus), and a layer-oriented wavefront sensor system optically performing... (More)
The adaptive optics for any telescope in the 25- to 100-m class will be complex. It is believed that adaptive optics should, to the maximum extent, be designed as an integrated part of a telescope. The proposed Swedish 50-m Extremely Large Telescope is considered here to illustrate the principle of integrated adaptive optics. Two alternative designs both using the Ritchey-Chretien telescope system and laser guide star (LGS) reference sources are presented. The first design employs trombone optics, which bring the laser guide star images back to the normal Ritchey-Chretien focal surface (referred to as the RC-focus) from the LGS focal surface (referred to as the LRC-focus), and a layer-oriented wavefront sensor system optically performing the averaging "shift and add" in the final focus. According to this procedure, sensed wavefronts are overlapped with a certain mutual shift and added for estimation of wavefront average slope values, resulting in actuator commands for driving the shape of the cleformable mirrors. The second design employs a numerical "shift and add" procedure and has two wavefront sensors. The first one performs LGS sensing in an intermediate focus (LRC-focus), giving the input data for an analytical algorithm for deriving the mirror deformations to correct for atmospheric turbulence. By using an artificial laser source at the intermediate focus, the shape of the second cleformable mirror is controlled by a second wavefront sensor in the final focus. The capability of the analytical algorithm to derive the mirror corrections from the measured wavefronts ensures proper functioning of the adaptive optics system. This system has a simpler optical design compared to the first design. (C) 2002 Society of Photo-Optical Instrumentation Engineers. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
wavefront sensors, adaptive optics, telescopes, optical systems
in
Optical Engineering
volume
41
issue
5
pages
1065 - 1072
publisher
SPIE
external identifiers
  • wos:000175583500022
  • scopus:0036576325
ISSN
0091-3286
DOI
10.1117/1.1466461
language
English
LU publication?
yes
id
81b4cb42-a970-4ab0-872e-08b51f014e24 (old id 337422)
date added to LUP
2007-08-20 16:45:38
date last changed
2017-01-01 06:44:10
@article{81b4cb42-a970-4ab0-872e-08b51f014e24,
  abstract     = {The adaptive optics for any telescope in the 25- to 100-m class will be complex. It is believed that adaptive optics should, to the maximum extent, be designed as an integrated part of a telescope. The proposed Swedish 50-m Extremely Large Telescope is considered here to illustrate the principle of integrated adaptive optics. Two alternative designs both using the Ritchey-Chretien telescope system and laser guide star (LGS) reference sources are presented. The first design employs trombone optics, which bring the laser guide star images back to the normal Ritchey-Chretien focal surface (referred to as the RC-focus) from the LGS focal surface (referred to as the LRC-focus), and a layer-oriented wavefront sensor system optically performing the averaging "shift and add" in the final focus. According to this procedure, sensed wavefronts are overlapped with a certain mutual shift and added for estimation of wavefront average slope values, resulting in actuator commands for driving the shape of the cleformable mirrors. The second design employs a numerical "shift and add" procedure and has two wavefront sensors. The first one performs LGS sensing in an intermediate focus (LRC-focus), giving the input data for an analytical algorithm for deriving the mirror deformations to correct for atmospheric turbulence. By using an artificial laser source at the intermediate focus, the shape of the second cleformable mirror is controlled by a second wavefront sensor in the final focus. The capability of the analytical algorithm to derive the mirror corrections from the measured wavefronts ensures proper functioning of the adaptive optics system. This system has a simpler optical design compared to the first design. (C) 2002 Society of Photo-Optical Instrumentation Engineers.},
  author       = {Gontcharov, Alexander and Owner-Petersen, Mette and Andersen, Torben and Beckers, JM},
  issn         = {0091-3286},
  keyword      = {wavefront sensors,adaptive optics,telescopes,optical systems},
  language     = {eng},
  number       = {5},
  pages        = {1065--1072},
  publisher    = {SPIE},
  series       = {Optical Engineering},
  title        = {Adaptive optics schemes for future extremely large telescopes},
  url          = {http://dx.doi.org/10.1117/1.1466461},
  volume       = {41},
  year         = {2002},
}