Design methodology to develop an active optics system for a thin 1-m meniscus mirror

Schwaer, Christian; Sinn, Andreas; Keller, Philipp; Schitter, Georg

doi:10.1117/1.jatis.6.4.049002

Cited by 3 publications

(5 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The mirror geometry is outlined in Schwaer et al. 2020 7 . Due to the lower mass of a glass mirror with equal geometry, the forces the lateral support system needs to take are larger with the aluminum mirror, which are considered insignificant for the purpose of this paper.…”

Section: System Descriptionmentioning

confidence: 99%

“…The number of actuators as well as their placement were derived by a finite element (FE) analysis where the mirror was pointed to horizon. With the requirement of 17 nm root mean square (RMS) error, 51 nm peak-valley error and considering the yield strength of borosilicate glass, the number of actuators are obtained to eight 7 . As mentioned in Sec.…”

Section: System Descriptionmentioning

confidence: 99%

“…1, electromechanical actuators are chosen due to their benefits. They are evenly distributed around the outer mirror edge and are oriented such that 70.4% of the total support force is applied tangentially and 29.6% radially 7 . Since the mirror cannot be supported at its center of gravity due to the meniscus shape, the lateral forces have components parallel to the optical axis in cosine distribution counted from the x-axis.…”

Section: System Descriptionmentioning

confidence: 99%

“…Since its invention, active optics systems were implemented in telescopes of varying sizes from 2.6 to 8.0 m due to following advantages: the optical tolerances are eased, thinner and more flexible mirrors are possible, the thermal time constant is reduced, the maintenance and alignment is simplified and new mirror materials can be considered 6 . This advantages also hold for smaller mirrors; however, as of now only few telescopes with diameters <4.0 m utilize active optics 7 . Implementing an active optics system in a medium-sized telescope with careful adaption of the actuation and sensing principles to smaller telescopes and different applications, such as space debris observation or optical satellite communication, promises to fulfill aforementioned requirements 7 …”

Section: Introductionmentioning

confidence: 99%

“…This advantages also hold for smaller mirrors; however, as of now only few telescopes with diameters <4.0 m utilize active optics 7 . Implementing an active optics system in a medium-sized telescope with careful adaption of the actuation and sensing principles to smaller telescopes and different applications, such as space debris observation or optical satellite communication, promises to fulfill aforementioned requirements 7 …”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Active lateral support system for a thin 1-meter meniscus mirror with virtual fixed points

Schwaer,

Sinn,

Schroeer

et al. 2023

J. Astron. Telesc. Instrum. Syst.

View full text Add to dashboard Cite

.This publication presents an active lateral support system for the thin 1-m meniscus mirror of a Ritchey-Chrétien telescope system. The goal is to keep the mirror at its position under varying external influences, such as gravity and temperature, therefore maintaining the alignment and optical image quality. To achieve this, the lateral support consists of eight actuators, based on stepper motors with gearboxes, with local force measurement and three laser triangulation sensors to measure the mirror’s lateral position. A cascaded control structure with local force feedback in the inner loop and position feedback in the outer loop is proposed. In the outer loop, three single-input single-output PI-controllers are implemented to maintain mirror position in the three lateral degrees of freedom. The developed system is able to position the mirror with root mean square errors of 0.27 and 0.18 μm in translational directions and 5.1 μrad in the rotational direction over the operational altitude range with a slewing speed of 0.2 deg / s.

show abstract

Section: System Descriptionmentioning

confidence: 99%

Section: System Descriptionmentioning

confidence: 99%