Active compensation of flexure on the High-Resolution Optical Spectrograph for Gemini

Paolo D'Arrigo, Francisco Diego, David D. Walker

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)

Abstract

Gravity-induced flexure has been a long-standing challenge in Cassegrain spectrographs at 4-meter class telescopes; it is the more so at the scale of 8-meter telescopes. This is of particular concern for the Gemini high resolution optical spectrograph, which will be Cassegrain-mounted for its routine mode of operation. In this paper we address the general flexure problem, and how to solve it with the use of active optics. We also present the results of an experimental active flexure compensation system for the ISIS (intermediate- dispersion spectroscopic and imaging system) spectrograph on the 4.2 m William Herschel Telescope (WHT). This instrument, called ISAAC (ISIS spectrograph automatic active collimator), is based on the concept of active correction, where spectrum drifts, due to the spectrograph flexing under the effect of gravity, are compensated by the movement of an active optical element (in this case a fine steering tip-tilt collimator mirror). The experiment showed that active compensation can reduce flexure down to less than 3 micrometer over four hours of telescope motions, dramatically improving the spectrograph performance. The results of the experiment are used to discuss a flexure compensation system for the high resolution optical spectrograph (HROS) for the 8 m Gemini telescope.

Original languageEnglish
Title of host publicationOptical Telescopes of Today and Tomorrow 1996
EditorsArne L. Ardeberg
PublisherSPIE
Pages1306-1317
Number of pages12
ISBN (Print)0819422681, 9780819422682
DOIs
Publication statusPublished - 21 Mar 1997
Externally publishedYes
EventOptical Telescopes of Today and Tomorrow - Landskrona/Hven, Swed
Duration: 29 May 199629 May 1996

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume2871
ISSN (Print)0277-786X

Conference

ConferenceOptical Telescopes of Today and Tomorrow
CityLandskrona/Hven, Swed
Period29/05/9629/05/96

Fingerprint

Spectrographs
flexing
spectrographs
Telescopes
high resolution
telescopes
collimators
Imaging systems
Gravitation
gravitation
Optical devices
Compensation and Redress
micrometers
Optics
Mirrors
Experiments
optics
mirrors

Cite this

D'Arrigo, P., Diego, F., & Walker, D. D. (1997). Active compensation of flexure on the High-Resolution Optical Spectrograph for Gemini. In A. L. Ardeberg (Ed.), Optical Telescopes of Today and Tomorrow 1996 (pp. 1306-1317). (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 2871). SPIE. https://doi.org/10.1117/12.269021
D'Arrigo, Paolo ; Diego, Francisco ; Walker, David D. / Active compensation of flexure on the High-Resolution Optical Spectrograph for Gemini. Optical Telescopes of Today and Tomorrow 1996. editor / Arne L. Ardeberg. SPIE, 1997. pp. 1306-1317 (Proceedings of SPIE - The International Society for Optical Engineering).
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D'Arrigo, P, Diego, F & Walker, DD 1997, Active compensation of flexure on the High-Resolution Optical Spectrograph for Gemini. in AL Ardeberg (ed.), Optical Telescopes of Today and Tomorrow 1996. Proceedings of SPIE - The International Society for Optical Engineering, vol. 2871, SPIE, pp. 1306-1317, Optical Telescopes of Today and Tomorrow, Landskrona/Hven, Swed, 29/05/96. https://doi.org/10.1117/12.269021

Active compensation of flexure on the High-Resolution Optical Spectrograph for Gemini. / D'Arrigo, Paolo; Diego, Francisco; Walker, David D.

Optical Telescopes of Today and Tomorrow 1996. ed. / Arne L. Ardeberg. SPIE, 1997. p. 1306-1317 (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 2871).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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AU - D'Arrigo, Paolo

AU - Diego, Francisco

AU - Walker, David D.

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N2 - Gravity-induced flexure has been a long-standing challenge in Cassegrain spectrographs at 4-meter class telescopes; it is the more so at the scale of 8-meter telescopes. This is of particular concern for the Gemini high resolution optical spectrograph, which will be Cassegrain-mounted for its routine mode of operation. In this paper we address the general flexure problem, and how to solve it with the use of active optics. We also present the results of an experimental active flexure compensation system for the ISIS (intermediate- dispersion spectroscopic and imaging system) spectrograph on the 4.2 m William Herschel Telescope (WHT). This instrument, called ISAAC (ISIS spectrograph automatic active collimator), is based on the concept of active correction, where spectrum drifts, due to the spectrograph flexing under the effect of gravity, are compensated by the movement of an active optical element (in this case a fine steering tip-tilt collimator mirror). The experiment showed that active compensation can reduce flexure down to less than 3 micrometer over four hours of telescope motions, dramatically improving the spectrograph performance. The results of the experiment are used to discuss a flexure compensation system for the high resolution optical spectrograph (HROS) for the 8 m Gemini telescope.

AB - Gravity-induced flexure has been a long-standing challenge in Cassegrain spectrographs at 4-meter class telescopes; it is the more so at the scale of 8-meter telescopes. This is of particular concern for the Gemini high resolution optical spectrograph, which will be Cassegrain-mounted for its routine mode of operation. In this paper we address the general flexure problem, and how to solve it with the use of active optics. We also present the results of an experimental active flexure compensation system for the ISIS (intermediate- dispersion spectroscopic and imaging system) spectrograph on the 4.2 m William Herschel Telescope (WHT). This instrument, called ISAAC (ISIS spectrograph automatic active collimator), is based on the concept of active correction, where spectrum drifts, due to the spectrograph flexing under the effect of gravity, are compensated by the movement of an active optical element (in this case a fine steering tip-tilt collimator mirror). The experiment showed that active compensation can reduce flexure down to less than 3 micrometer over four hours of telescope motions, dramatically improving the spectrograph performance. The results of the experiment are used to discuss a flexure compensation system for the high resolution optical spectrograph (HROS) for the 8 m Gemini telescope.

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M3 - Conference contribution

SN - 0819422681

SN - 9780819422682

T3 - Proceedings of SPIE - The International Society for Optical Engineering

SP - 1306

EP - 1317

BT - Optical Telescopes of Today and Tomorrow 1996

A2 - Ardeberg, Arne L.

PB - SPIE

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D'Arrigo P, Diego F, Walker DD. Active compensation of flexure on the High-Resolution Optical Spectrograph for Gemini. In Ardeberg AL, editor, Optical Telescopes of Today and Tomorrow 1996. SPIE. 1997. p. 1306-1317. (Proceedings of SPIE - The International Society for Optical Engineering). https://doi.org/10.1117/12.269021