GMT adaptive secondary design

R. Biasi, D. Veronese, M. Andrighettoni, G. Angerer, D. Gallieni, M. Mantegazza, M. Tintori, P. Lazzarini, M. Manetti, M. W. Johns, Philip M Hinz, J. Kern

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

16 Citations (Scopus)

Abstract

The GMT adaptive secondary mirror (ASM) is based on a "segmented" concept following the primary segment layout: seven 1.05m diameter circular, independent adaptive mirrors are fed by the primaries and focus to the main telescope focal stations. The adaptive unit's design is based on the consolidated thin mirror, contactless technology already employed in several units (MMT, LBT, Magellan, VLT and one of the proposed E-ELT M4 designs), but nevertheless the mirror's topology reveals several design challenges. In particular, the off-axis units are strongly aspheric and therefore they require aspheric shaping of both thin mirror surfaces and of the thick reference body. The strong tilt of the off-axis units forced us to consider a peculiar fine positioning hexapod design, maximizing its stiffness and also implementing a special design of the last three rings of actuators to remain within the prescribed obstruction. From the control point of view, the actuator density of the adaptive mirrors is remarkably lower than in all previous units: 672 actuators with 36mm spacing compared to 30mm typical separation adopted so far. This choice is validated by static and dynamic performance computation though a sophisticated numerical simulator based on a full state space model incorporating mechanics, control and fluid dynamics. The control system fulfills the dimensional constraints of the unit. The design has completed the feasibility phase, including the cost estimate. The choice of making the GMT adaptive secondary mirrors similar to the already existing ones strongly reduces the implementation risks and allows shortening the remaining design path.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
Volume7736
EditionPART 1
DOIs
StatePublished - 2010
Externally publishedYes
EventAdaptive Optics Systems II - San Diego, CA, United States
Duration: Jun 27 2010Jul 2 2010

Other

OtherAdaptive Optics Systems II
CountryUnited States
CitySan Diego, CA
Period6/27/107/2/10

Fingerprint

Mirror
mirrors
Unit
Mirrors
Actuator
Actuators
actuators
cost estimates
Hexapod
dynamic control
Dynamic Performance
State-space Model
fluid dynamics
Tilt
Fluid Dynamics
Fluid dynamics
Design
Obstruction
Telescopes
layouts

Keywords

  • Adaptive mirrors
  • Adaptive optics
  • Adaptive secondary
  • Deformable mirrors
  • GMT
  • Hexapod

ASJC Scopus subject areas

  • Applied Mathematics
  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Biasi, R., Veronese, D., Andrighettoni, M., Angerer, G., Gallieni, D., Mantegazza, M., ... Kern, J. (2010). GMT adaptive secondary design. In Proceedings of SPIE - The International Society for Optical Engineering (PART 1 ed., Vol. 7736). [77363O] https://doi.org/10.1117/12.857983

GMT adaptive secondary design. / Biasi, R.; Veronese, D.; Andrighettoni, M.; Angerer, G.; Gallieni, D.; Mantegazza, M.; Tintori, M.; Lazzarini, P.; Manetti, M.; Johns, M. W.; Hinz, Philip M; Kern, J.

Proceedings of SPIE - The International Society for Optical Engineering. Vol. 7736 PART 1. ed. 2010. 77363O.

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

Biasi, R, Veronese, D, Andrighettoni, M, Angerer, G, Gallieni, D, Mantegazza, M, Tintori, M, Lazzarini, P, Manetti, M, Johns, MW, Hinz, PM & Kern, J 2010, GMT adaptive secondary design. in Proceedings of SPIE - The International Society for Optical Engineering. PART 1 edn, vol. 7736, 77363O, Adaptive Optics Systems II, San Diego, CA, United States, 6/27/10. https://doi.org/10.1117/12.857983
Biasi R, Veronese D, Andrighettoni M, Angerer G, Gallieni D, Mantegazza M et al. GMT adaptive secondary design. In Proceedings of SPIE - The International Society for Optical Engineering. PART 1 ed. Vol. 7736. 2010. 77363O https://doi.org/10.1117/12.857983
Biasi, R. ; Veronese, D. ; Andrighettoni, M. ; Angerer, G. ; Gallieni, D. ; Mantegazza, M. ; Tintori, M. ; Lazzarini, P. ; Manetti, M. ; Johns, M. W. ; Hinz, Philip M ; Kern, J. / GMT adaptive secondary design. Proceedings of SPIE - The International Society for Optical Engineering. Vol. 7736 PART 1. ed. 2010.
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