Active Optics in Astronomy: Freeform Mirror for the MESSIER Telescope Proposal

Active optics techniques in astronomy provide high imaging quality. This paper is dedicated to highly deformable active optics that can generate non-axisymmetric aspheric surfaces—or freeform surfaces—by use of a minimum number of actuators. The aspheric mirror is obtained from a single uniform load that acts over the surface of a closed-form substrate whilst under axial reaction to its elliptical perimeter ring during spherical polishing. MESSIER space proposal is a wide-field low-central-obstruction folded-two-mirror-anastigmat or here called briefly three-mirror-anastigmat (TMA) telescope. The optical design is a folded reflective Schmidt. Basic telescope features are 36 cm aperture, f/2.5, with 1.6° × 2.6° field of view and a curved field detector allowing null distortion aberration for drift-scan observations. The freeform mirror is generated by spherical stress polishing that provides super-polished freeform surfaces after elastic relaxation. Preliminary analysis required use of the optics theory of 3rd-order aberrations and elasticity theory of thin elliptical plates. Final cross-optimizations were carried out with Zemax raytracing code and Nastran FEA elasticity code in order to determine the complete geometry of a glass ceramic Zerodur deformable substrate.

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Active optics in astronomy – modeling of deformable substrates: freeform surfaces for FIREBall and MESSIER

Journal of the Mechanical Behavior of Materials ◽

10.1515/jmbm-2018-2008 ◽

2018 ◽

Vol 27 (5-6) ◽

Cited By ~ 1

Author(s):

Gérard Rene Lemaitre

Keyword(s):

Adaptive Optics ◽

Large Scale ◽

Wide Field ◽

Freeform Surfaces ◽

Aspheric Surfaces ◽

Massive Black Holes ◽

Active Optics ◽

Minimum Number ◽

Co Addition ◽

Large Telescopes

AbstractActive optics techniques on large telescopes and astronomical instrumentations provide high imaging quality. For ground-based astronomy, the co-addition of adaptive optics again increases angular resolution up to providing diffraction-limited imaging at least in the infrared. Active and adaptive optics marked milestone progress in the detection of exoplanets, super-massive black holes, and large-scale structure of galaxies. This paper is dedicated to highly deformable active optics that can generate non-axisymmetric aspheric surfaces – or freeform surfaces – by use of a minimum number of actuators: a single uniform load acts over the surface of a vase-form substrate whilst under reaction to its elliptical perimeter ring. Two such instruments are presented: (1) the Faint Intergalactic Redshifted Emission Balloon (FIREBall) telescope and multi object spectrograph (MOS) where the freeform reflective diffraction grating is generated by replication of a deformable master grating, and (2) the MESSIER wide-field low-central-obstruction three-mirror-anastigmat (TMA) telescope proposal where the freeform mirror is generated by stress figuring and elastic relaxation. Freeform surfaces were obtained by plane super-polishing. Preliminary analysis required use of the optics theory of 3rd-order aberrations and elasticity theory of thin elliptical plates. Final cross-optimizations were carried out with Zemax raytracing code and Nastran FEA elasticity code in order to determine geometry of the deformable substrates.

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Optical Design of the Goaly3 Multi-Mirror Telescope System with a Wide Field of View

Applied Sciences ◽

10.3390/app11031200 ◽

2021 ◽

Vol 11 (3) ◽

pp. 1200

Author(s):

Junliu Fan ◽

Quanying Wu ◽

Baohua Chen ◽

Lin Liu ◽

Lei Chen

Keyword(s):

Fill Factor ◽

Optical Design ◽

Tolerance Analysis ◽

Field Of View ◽

Wide Field ◽

Aspheric Surfaces ◽

The Monte Carlo Method ◽

Wide Field Of View ◽

Mirror Telescope ◽

Telescope System

A Golay3 multi-mirror telescope (MMT) system is designed in this paper. The fill factor of the Golay3 MMT is derived from the angular resolution of the telescope. An initial configuration is established according to the paraxial optical theory. A three-element aspheric corrector group is designed and placed in the converging light cone to enlarge the field of view (FOV) of the Golay3 MMT. The tolerance analysis for each surface of the Golay3 MMT is conducted using the Monte Carlo method. The design results show the FOV of the Golay3 MMT system can be increased to 1.5° with the insertion of a three-element aspheric corrector group. The results of the tolerance analysis indicate that most tolerances are loose, while some decenter tolerances relating with the aspheric surfaces are relatively tight, but still within an acceptable range.

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Optical design of wide field of view achromatic phase retarders

10.1117/12.617063 ◽

2005 ◽

Author(s):

Apostolos Deslis

Keyword(s):

Optical Design ◽

Field Of View ◽

Wide Field ◽

Wide Field Of View ◽

Phase Retarders

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Optical Design for a Head-Mounted Display

Presence Teleoperators & Virtual Environments ◽

10.1162/pres.1993.2.3.185 ◽

1993 ◽

Vol 2 (3) ◽

pp. 185-202 ◽

Cited By ~ 3

Author(s):

Jiantao Ma ◽

John M. Hollerbach ◽

Ian W. Hunter

Keyword(s):

Optical Design ◽

Field Of View ◽

Wide Field ◽

Optical System Design ◽

Head Mounted Display ◽

Cost Constraints ◽

Field Curvature ◽

Folded Structure ◽

Wide Field Of View ◽

Color Field

This paper presents a design concept for a head-mounted display, incorporating color stereo vision using commercial LCDs and our own optical relay design. The focus here is on the optical system design, which must meet specifications for a wide field of view, size and cost constraints, and aberration minimization based on human factors. Two multispherical lens systems are presented and compared, one a straight structure and the other a folded structure, which satisfy the design constraints. Their aberrations (distortion, coma, lateral color, field curvature, and astigmatism) have been well corrected, according to human perceptual constraints explicitly discussed. Each has a 20-mm eye relief and an instantaneous field of view greater than 60°; the former has an exit pupil of 10 mm and the latter of 8 mm.

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