The alignment of the aerospace Cassegrain telescope primary mirror and iso-static mount by using CMM

Lin, Wei-Cheng; Chang, Shenq-Tsong; Lin, Yung-Hsiang; Cheng, Yu-Cheng; Hsu, Ming-Ying; Huang, Ting-Ming

doi:10.1117/12.894379

Cited by 3 publications

(3 citation statements)

References 4 publications

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“…Howick et al (2007) 3 showed that CMM can be used in the metrology of lenses and alignment process. Lin et al (2011) 4 also used a CMM machine to verify the orientation of the Cassegrain telescope's primary mirror and the orientation adjustment of its mechanical ground support equipment. Lin et al (2012) 5 expanded their previous work by using a CMM to verify the bonding technique of the space telescope.…”

Section: Introductionmentioning

confidence: 99%

Repositioning and locking method for off-axis optical system using mechanical measurement

Sukanunta,

Jitklongsub,

Phlernjai

et al. 2023

Optifab 2023

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Section: Introductionmentioning

confidence: 99%

Repositioning and locking method for off-axis optical system using mechanical measurement

Sukanunta,

Jitklongsub,

Phlernjai

et al. 2023

Optifab 2023

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“…W.C. Lin and S.T. Chang presented the alignment procedure of primary mirror of cassegrain telescope by using CMM, and the post-analyzing algorithm of optical parameter from the CMM measured raw data by using optical software is precise and useful for the alignment of the mid-large opto-mechanical system 9 .…”

Section: Introductionmentioning

confidence: 99%

The alignment and isostatic mount bonding technique of the aerospace Cassegrain telescope primary mirror

Lin¹,

Chang²,

Lin³

et al. 2012

SPIE Proceedings

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In order to meet both optical performance and structural stiffness requirements of the aerospace Cassegrain telescope, iso-static mount is used as the interface between the primary mirror and the main plate. This article describes the alignment and iso-static mount bonding technique of the primary mirror by assistance of CMM. The design and assembly of mechanical ground support equipment (MGSE) which reduces the deformation of primary mirror by the gravity effect is also presented. The primary mirror adjusting MGSE consists of X-Y linear translation stages, rotation stage and kinematic constrain platform which provides the function of decenter, orientation, tilt and height adjustment of the posture sequentially. After CMM measurement, the radius of curvature, conic constant, decenter and tilt, etc. will be calculated. According to these results, the posture of the mirror will be adjusted to reduce the tilt by the designed MGSE within 0.02 degrees and the distance deviation from the best fitted profile of mirror to main plate shall be less than 0.01 mm. After that, EC 2216 adhesive is used to bond mirror and iso-static mount. During iso-static mount bonding process, CMM is selected to monitor the relative position deviation of the iso-static mount until the adhesive completely cured. After that, the wave front sensors and strain gauges are used to monitor the strain variation while the iso-static mount mounted in the main plate with the screws by the torque wrench. This step is to prevent deformation of the mirror caused from force of the iso-static mount during the mounting process. In the end, the interferometer is used for the optical performance test with +1G and -1G to check the alignment and bonding technique is well or not.

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“…The method is a precise and useful method for aligning mid-size to large optomechanical systems. 5,6 Kihm et al proposed a novel design for adjustable bipod flexures used to mount mirrors and conduct optical experiments on a space telescope. The design reduced the error caused by the gravity effect to less than root mean square 10 nm.…”

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Alignment and assembly process for primary mirror subsystem of a spaceborne telescope

Lin

Chang

et al. 2015

Opt. Eng

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Abstract. In this study, a multispectral spaceborne Cassegrain telescope was developed. The telescope was equipped with a primary mirror with a 450-mm clear aperture composed of Zerodur and lightweighted at a ratio of approximately 50% to meet both thermal and mass requirements. Reducing the astigmatism was critical for this mirror. The astigmatism is caused by gravity effects, the bonding process, and deformation from mounting the main structure of the telescope (main plate). This article presents the primary mirror alignment, mechanical ground-supported equipment (MGSE), assembly process, and optical performance test used to assemble the primary mirror. A mechanical compensated shim is used as the interface between the bipod flexure and main plate. The shim was used to compensate for manufacturer errors found in components and differences between local coplanarity errors to prevent stress while the bipod flexure was screwed to the main plate. After primary mirror assembly, an optical performance test method called a bench test with an algorithm was used to analyze the astigmatism caused by the gravity effect and deformation from the mounting or supporter. The tolerance conditions for the primary mirror assembly require the astigmatism caused by gravity and mounting force deformation to be less than P − V 0.02 λ at 632.8 nm. The results demonstrated that the designed MGSE used in the alignment and assembly processes met the critical requirements for the primary mirror assembly of the telescope. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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The alignment of the aerospace Cassegrain telescope primary mirror and iso-static mount by using CMM

Cited by 3 publications

References 4 publications

Repositioning and locking method for off-axis optical system using mechanical measurement

Repositioning and locking method for off-axis optical system using mechanical measurement

The alignment and isostatic mount bonding technique of the aerospace Cassegrain telescope primary mirror

Alignment and assembly process for primary mirror subsystem of a spaceborne telescope

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