Correcting secondary mirror surface errors in Noto 32 m radiotelescope using the ‘active’ primary mirror

2003 ◽  
Vol 39 (5) ◽  
pp. 416 ◽  
Author(s):  
P. Bolli ◽  
G. Grueff
Keyword(s):  
Mirror Surface ◽  
Primary Mirror ◽  
Surface Errors ◽  
Secondary Mirror

scholarly journals Precision Analysis and Error Compensation of a Telescope Truss Structure Based on Robotics

2020 ◽  
Vol 10 (18) ◽  
pp. 6424
Author(s):  
Rui Wang ◽  
Fuguo Wang ◽  
Yuyan Cao ◽  
Honghao Wang ◽  
Xueqian Sun ◽  
...  
Keyword(s):  
Engineering Application ◽  
High Order ◽  
Wavefront Aberration ◽  
Mirror Surface ◽  
Sensitivity Matrix ◽  
Support Structure ◽  
Inverse Kinematic Problem ◽  
Surface Error ◽  
Primary Mirror ◽  
Secondary Mirror

We propose a new secondary mirror support structure assisted by multi-robotics to improve the observation performance of vehicle-mobile telescope systems. A mathematical model of the displacement at the end of the robotic and the variation of telescope pitch angle is established, then the posture of the robotic is optimized by the Jacobian matrix iteration inverse kinematic problem method. Based on the new support structure, a high-order sensitivity matrix is proposed to establish the mapping relationship between the robotic misalignment and the Zernike coefficient, with the accuracy verified via the Monte Carlo method. The method of adjusting the secondary mirror to compensate the aberration caused by the primary mirror is proposed, and the relationship between the primary mirror surface error and the system error is established under different pitch angles before and after compensation. The experiment and simulation results showed that the adjustment calculated by the high-order sensitivity matrix method can effectively compensate for the misalignment caused by the robotics and the primary mirror surface error to a certain degree. After multiple iterations, the root mean square of the wavefront aberration was better than λ/15. This conclusion provides an engineering application reference value for the secondary mirror support and aberration correction technology of the vehicle telescope system.

Optimization Analysis for Radial Support by Finite Elements Method

2012 ◽  
Vol 466-467 ◽  
pp. 734-738
Author(s):  
Cheng Ming Li ◽  
Yi Fan Wang
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Optimal Solution ◽  
Support Point ◽  
Mirror Surface ◽  
Optimization Analysis ◽  
Primary Mirror ◽  
Finite Element Software ◽  
The Relationship ◽  
Surface Figure

Primary mirror’ surface figure is affected by supporting structure obviously. Especially for large-aperture telescope, the surface figure is significant because of primary mirror’ self-weight. For the requirement of the usage, it’s necessary to minimize the surface figure from self-weight by reasonable supporting scheme. The text optimized support point and force of radial support to minimize the surface figure by finite-element software. At the same time, it studied the relationship between support point and counterweight to reduce the weight of support structure. At last, it gave the optimal solution.

Design and analysis of supporting structure between the primary mirror and the secondary mirror on a space telescope

2015 ◽  
Author(s):  
Chenjie Wang ◽  
Wenyi Chai ◽  
Liangjie Feng ◽  
Wengang Yang ◽  
Wei Wang ◽  
...  
Keyword(s):  
Space Telescope ◽  
Primary Mirror ◽  
Supporting Structure ◽  
Secondary Mirror

scholarly journals Optical Design of a Novel Two-Stage Dish Applied to Thermochemical Water/CO2 Splitting with the Concept of Rotary Secondary Mirror

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3553
Author(s):  
Song Yang ◽  
Jun Wang ◽  
Peter D. Lund
Keyword(s):  
Mathematical Model ◽  
Ray Tracing ◽  
Concentration Ratio ◽  
Thermal Water ◽  
Optical Design ◽  
Two Stage ◽  
Optical Efficiency ◽  
Primary Mirror ◽  
Secondary Mirror ◽  
Ray Tracing Simulation

In this paper, a novel two-stage dish concentrator (TSD) with a rotary secondary mirror (SM) is presented for solar thermal water/CO2 splitting. An in-house code for ray-tracing simulation of the concentrator was developed and validated. Among all feasible geometries, a hyperboloid with an upper sheet is the most popular option and is widely used as a secondary reflector, which is mainly discussed here. All para-hyperboloid geometric combinations can be categorized into three typical patterns (φ1 < π/2, φ1 = π/2, φ1 > π/2, φ1 = field angle of PM). The initial designs of the TSD, respective to different off-axis levels for each combination, were first designed. Then a new mathematical model was introduced to reshape the SM to reach optimal truncated designs. Finally, a new concept of an off-axis primary mirror (PM) combined with the truncated SM was evaluated by using the in-house ray-tracing code. The results include the optical efficiency, concentration ratio and intercepted radiant flux. The best solutions with the highest optical efficiency fall in the range π/2 ≤ φ1 ≤ (π − arcsin 0.8) rads and 0.4 ≤ NA2 ≤ 0.6 (NA2 = sin φ2, φ2 = field angle of SM), which vary with the concentration ratio and inclination angle.

scholarly journals Optical telescope with Cassegrain metasurfaces

Nanophotonics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 3263-3269 ◽  
Author(s):  
Xuan Liu ◽  
Junhong Deng ◽  
King Fai Li ◽  
Mingke Jin ◽  
Yutao Tang ◽  
...  
Keyword(s):  
Near Infrared ◽  
Incident Light ◽  
Astronomical Observation ◽  
Optical Telescope ◽  
Circularly Polarized ◽  
Primary Mirror ◽  
Secondary Mirror ◽  
Infrared Wavelengths ◽  
Cassegrain Telescope ◽  
Imaging Properties

AbstractThe Cassegrain telescope, made of a concave primary mirror and a convex secondary mirror, is widely utilized for modern astronomical observation. However, the existence of curved mirrors inevitably results in bulky configurations. Here, we propose a new design of the miniaturized Cassegrain telescope by replacing the curved mirrors with planar reflective metasurfaces. The focusing and imaging properties of the Cassegrain metasurface telescopes are experimentally verified for circularly polarized incident light at near infrared wavelengths. The concept of the metasurface telescopes can be employed for applications in telescopes working at infrared, Terahertz, and microwave and even radio frequencies.

scholarly journals Design and Optimization for Mounting Primary Mirror with Reduced Sensitivity to Temperature Change in an Aerial Optoelectronic Sensor

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7993
Author(s):  
Meijun Zhang ◽  
Qipeng Lu ◽  
Haonan Tian ◽  
Dejiang Wang ◽  
Cheng Chen ◽  
...  
Keyword(s):  
Surface Shape ◽  
Shape Error ◽  
Temperature Decrease ◽  
Mirror Surface ◽  
Optical Performance ◽  
Uniform Temperature ◽  
Primary Mirror ◽  
Optoelectronic Sensor ◽  
Thermal Adaptability

In order to improve the image quality of the aerial optoelectronic sensor over a wide range of temperature changes, high thermal adaptability of the primary mirror as the critical components is considered. Integrated optomechanical analysis and optimization for mounting primary mirrors are carried out. The mirror surface shape error caused by uniform temperature decrease was treated as the objective function, and the fundamental frequency of the mirror assembly and the surface shape error caused by gravity parallel or vertical to the optical axis are taken as the constraints. A detailed size optimization is conducted to optimize its dimension parameters. Sensitivities of the optical system performance with respect to the size parameters are further evaluated. The configuration of the primary mirror and the flexure are obtained. The simulated optimization results show that the size parameters differently affect the optical performance and which factors are the key. The mirror surface shape error under 30 °C uniform temperature decrease effectively decreased from 26.5 nm to 11.6 nm, despite the weight of the primary mirror assembly increases by 0.3 kg. Compared to the initial design, the value of the system’s modulation transfer function (0° field angle) is improved from 0.15 to 0.21. Namely, the optical performance of the camera under thermal load has been enhanced and thermal adaptability of the primary mirror has been obviously reinforced after optimization. Based on the optimized results, a prototype of the primary mirror assembly is manufactured and assembled. A ground thermal test was conducted to verify difference in imaging quality at room and low temperature, respectively. The image quality of the camera meets the requirements of the index despite degrading.

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