Specifications and design of the E-ELT M4 adaptive unit

Vernet, Elise; Cayrel, Marc; Hubin, N.; Mueller, Martin; Biasi, Roberto; Gallieni, Daniele; Tintori, Matteo

doi:10.1117/12.925133

Cited by 15 publications

(9 citation statements)

References 6 publications

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“…Phase C will introduce the full configuration proposed for EAGLE. We will use a woofer DM in closed-loop (in fact the 8 × 8 actuator DM), as a first stage simulating M4 of the E-ELT (Vernet et al 2012) with an open-loop tweeter DM as a second stage simulating the MOAO channel. The tweeter DM in Phase C will be a higher-order DM from ALPAO with 17 × 17 actuators (241 useful).…”

Section: Introductionmentioning

confidence: 99%

Analysis of on-sky MOAO performance of CANARY using natural guide stars

Vidal

Gendron

Rousset

et al. 2014

A&A

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The first on-sky results obtained by CANARY, the multi-object adaptive optics (MOAO) demonstrator, are analysed. The data were recorded at the William Herschel Telescope, at the end of September 2010. We describe the command and calibrations algorithms used during the run and present the observing conditions. The processed data are MOAO-loop engaged or disengaged slopes buffers, comprising the synchronised measurements of the four natural guide stars (NGS) wavefront sensors running in parallel, and near infrared (IR) images. We describe the method we use to establish the error budget of CANARY. We are able to evaluate the tomographic and the open loop errors, having median values around 216 nm and 110 nm respectively. In addition, we identify an unexpected residual quasi-static field aberration term of mean value 110 nm. We present the detailed error budget analysed for three sets of data for three different asterisms. We compare the experimental budgets with the numerically simulated ones and demonstrate a good agreement. We find also a good agreement between the computed error budget from the slope buffers and the measured Strehl ratio on the IR images, ranging between 10% and 20% at 1530 nm. These results make us confident in our ability to establish the error budget of future MOAO instruments.

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Section: Introductionmentioning

confidence: 99%

Analysis of on-sky MOAO performance of CANARY using natural guide stars

Vidal

Gendron

Rousset

et al. 2014

A&A

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“…The E-ELT project is a three mirror anastigmat including addition of a pupil transfer between a pair of flat mirrors, adaptive mirror M 4 and field stabilization mirror M 5 , which fold the beams along the elevation axis to the Nasmyth foci (Delabre [32], Vernet et al [33]). The ADM of a segment is minimized by an axial support system called a whiffletree -a superimposition of pivot trianglesmounted on the tripod frames.…”

Section: Segments Of Large Telescope Mirrorsmentioning

confidence: 99%

Active optics with a minimum number of actuators

Lemaitre

2014

Advanced Optical Technologies

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Optics for astronomy implies powerful developments of active and adaptive optics methods applied to instrumentation from X-rays to the near infrared for the design of telescopes, spectrographs, and coronagraph planet finders. This presentation particularly emphasizes the development of active optics methods. Highly accurate and remarkably smooth surfaces from active optics methods allow new optical systems that use highly aspheric and non-axisymmetric -freeform -surfaces. Depending on the goal and performance required for a deformable optical surface, elasticity theory analysis is carried out either with small deformation thin plate theory, large deformation thin plate theory, shallow spherical shell theory, or the weakly conical shell theory. A mirror thickness distribution is then determined as a function of associated bending actuators and boundary conditions. For a given optical shape to generate, one searches for optical solutions with a minimum number of actuators.

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“…M4AU will be a flat, 2.4-m diameter, segmented deformable mirror which shall be controlled by ~5000 voice-coil actuators 1 , enhancing the current state-of-the-art technology proven on sky, e.g. with the Large Binocular Telescope adaptive secondary mirrors 2 .…”

Section: Introductionmentioning

confidence: 99%

Optical calibration and testing of the E-ELT M4 adaptive mirror

et al. 2012

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Innovative optical interferometry test setups and control software techniques have been proposed for the E-ELT M4 adaptive optics mirror. The system is composed of three sub-systems: a CGH-based optical test tower, delivering a 1.5-m collimated beam, for fast simultaneous acquisition of large areas; a stitching interferometer, to calibrate at higher spatial frequencies, on smaller areas; and an optical piston sensor to remove differential piston and tilt between adjacent mirror segments.

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Specifications and design of the E-ELT M4 adaptive unit

Cited by 15 publications

References 6 publications

Analysis of on-sky MOAO performance of CANARY using natural guide stars

Analysis of on-sky MOAO performance of CANARY using natural guide stars

Active optics with a minimum number of actuators

Optical calibration and testing of the E-ELT M4 adaptive mirror

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