Fast optical re-phasing of segmented primary mirrors

Bonnet, Henri; Esselborn, Michael; Kornweibel, Nick; Dierickx, Philippe

doi:10.1117/12.2057457

Cited by 4 publications

(2 citation statements)

References 4 publications

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“…Various methods have been implemented for extending the capture range beyond several microns. These include implementing multicolour schemes [19,20] and measuring light coherence by modulating the segments [11,21]. However, these methods rely on modulating the segments' piston and therefore cannot be used in parallel with science observations.…”

Section: Introductionmentioning

confidence: 99%

Measuring the cophasing state of a segmented mirror with a wavelength sweep and a Zernike phase contrast sensor

Cheffot¹,

Vigan²,

Lévêque³

et al. 2020

Opt. Express

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The demand for higher resolution telescopes leads to segmented primary mirrors which need to be phased for operation. A phasing sensor applying a wavelength sweep technique provides a large capture range without modulating the position of individual mirror segments. This technique offers the potential to monitor the phasing state of a segmented telescope in parallel to the science observations. We evaluate the performance of the wavelength sweep technique using a Zernike phase contrast sensor for coarse phasing. Tests results on a dedicated bench show 112 nm rms precision. With the help of a simulation, we explain a known error of the method and we suggest ways for improvements.

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Section: Introductionmentioning

confidence: 99%

Measuring the cophasing state of a segmented mirror with a wavelength sweep and a Zernike phase contrast sensor

Cheffot¹,

Vigan²,

Lévêque³

et al. 2020

Opt. Express

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“…To build a more than ten-meter aperture telescope, the technology of segmented mirror should be used, just as adopted in Keck, thirty meter telescope (TMT), and European extremely large telescope (E-ELT). [1][2][3][4] But the segmented mirror technology brings about new problems, one of which is that the assembly error of segmented mirror seriously affects the resolution of the telescope. So, only when the segmented mirror is co-focus and co-phasing, can it reach the resolution corresponding to the aperture of segmented mirror.…”

Section: Introductionmentioning

confidence: 99%

Co-focus experiment of segmented mirror

Li¹,

Yu²,

Chen³

et al. 2017

Chinese Phys. B

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In this paper, an active optics and co-focus experimental system of segmented mirror is built. Firstly, a support structure of segmented mirror is designed and it is verified by simulation to meet the requirement for the experimental system of segmented mirror. In this system, the large de-focus and tilt/tip errors of the segmented mirror are adjusted by observing the density and contrast of interference fringes based on isoclinic interference theory until the defocus and tilt/tip errors are in the detective range of the Shack-Hartmann. Then, the Shack-Hartmann is used to measure them and they are adjusted by actuators. The actuators are controlled by active optics to realize the closed-loop adjustment and maintenance for fine co-focus of segmented mirror. And the interference fringes are utilized to verify the detective precision of Shack-Hartmann. After the co-focus fine-tuning of the segmented mirror, the tilt/tip residual surface error is better than 0.01λ RMS; the defocus residual surface error is better than 0.01λ RMS.

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A Novel Dual-Differential Edge Sensor Based on the Eddy Current Effect

Zhao

Feng

2023

IEEE Sensors J.

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Fast optical re-phasing of segmented primary mirrors

Cited by 4 publications

References 4 publications

Measuring the cophasing state of a segmented mirror with a wavelength sweep and a Zernike phase contrast sensor

Measuring the cophasing state of a segmented mirror with a wavelength sweep and a Zernike phase contrast sensor

Co-focus experiment of segmented mirror

A Novel Dual-Differential Edge Sensor Based on the Eddy Current Effect

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