On the sequence of deformable mirrors in MCAO: Findings from an on-sky, closed-loop experiment

Dirk Schmidt, Nicolas Gorceix, Philip Goode

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

1 Scopus citations

Abstract

We performed an on-sky MCAO experiment using 4 deformable mirrors (DMs) to analyze the relevance of their sequence to the residual wavefront error. Two DMs were conjugate to 4 and 8 km. The other two DMs were placed in pupil images upstream and downstream of the 4-km and 8-km mirrors. At any time, both high altitude DMs were active but only one pupil DM was active while the other one stayed flat. Firstly, we found that the MCAO control loops using either pupil DM were stable and robust. Dynamic misregistration, which was present for the first pupil DM, was not an immediate problem for the controller. We did not notice an apparent difference when repeatedly switching between the pupil DMs during the operation. A closer analysis of the contrast in the corrected images and AO telemetry indicates an advantage when the pupil correction was applied with the DM that was downstream of the high-altitude DMs. This finding is consistent in several data recorded at different days. The difference, however, is small. A more detailed analysis is probably needed to rule out error sources potentially not considered herein to draw a final conclusion on the optimal sequence of DMs in MCAO and its practical relevance.

Original languageEnglish (US)
Title of host publicationAdaptive Optics Systems VII
EditorsLaura Schreiber, Dirk Schmidt, Elise Vernet
PublisherSPIE
ISBN (Electronic)9781510636835
DOIs
StatePublished - 2020
EventAdaptive Optics Systems VII 2020 - Virtual, Online, United States
Duration: Dec 14 2020Dec 22 2020

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume11448
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Conference

ConferenceAdaptive Optics Systems VII 2020
Country/TerritoryUnited States
CityVirtual, Online
Period12/14/2012/22/20

All Science Journal Classification (ASJC) codes

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

Keywords

  • Clear
  • Dynamic misregistration
  • Multi-conjugate adaptive optics
  • Sequence of deformable mirrors

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