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Metrology camera system of prime focus spectrograph for Subaru telescope

Wang, Shiang-Yu and Chou, Richard C. Y. and Huang, Pin-Jie and Chang, Yin-Chang and Ling, Hung-Hsu and Yan, Chi-Hung and Karr, Jennifer and Hsu, Shu-Fu and Chen, Hsin-Yo and Hu, Yen-Sang and Gunn, James E. and Reiley, Dan J. and Tamura, Naoyuki and Takato, Naruhisa and Moritani, Yuki and Shimono, Atsushi (2018) Metrology camera system of prime focus spectrograph for Subaru telescope. In: Ground-based and Airborne Instrumentation for Astronomy VII. Proceedings of SPIE. No.10702. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 107027H. ISBN 9781510619579.

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The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph designed for the prime focus of the 8.2m Subaru telescope. PFS will cover a 1.3 degree diameter field with 2394 fibers to complement the imaging capabilities of Hyper SuprimeCam. To retain high throughput, the final positioning accuracy between the fibers and observing targets of PFS is required to be less than 10 μm. The metrology camera system (MCS) serves as the optical encoder of the fiber positioners for the configuring of fibers. MCS provides the fiber positions within a 5 microns error over the 45 cm focal plane. The information from MCS will be fed into the fiber positioner control system for the closed loop control. MCS locates at the Cassegrain focus of Subaru telescope to cover the whole focal plan with one 50M pixel Canon CMOS camera. It is a 380 mm aperture Schmidt type telescope which generates uniform spot size around 10 µm FWHM across the field for reasonable sampling of the point spreading function. An achromatic lens set is designed to remove the possible chromatic error due to the variation of the LED wavelength. Carbon fiber tubes are used to provide stable structure over the operation conditions without focus adjustments. The CMOS sensor can be read in 0.8 s to reduce the overhead for the fiber configuration. The positions of all fibers can be obtained within 0.5 s after the readout of the frame. This enables the overall fiber configuration to be less than 2 minutes. MCS is installed inside a standard Subaru Cassgrain Box. All components generate heat are located inside a glycol cooled cabinet to reduce the possible image motion due to the heat. The integration of MCS started from fall 2017 and it was delivered to Subaru in April 2018. In this report, the performance of MCS after the integration and verification process in ASIAA and the performance after the delivery to Subaru telescope are presented.

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Additional Information:© 2018 Society of Photo-Optical Instrumentation Engineers (SPIE). We gratefully acknowledge support from the Funding Program for World-Leading Innovative R&D on Science and Technology(FIRST) “Subaru Measurements of Images and Redshifts (SuMIRe)”, CSTP, Japan for PFS project. The work in ASIAA, Taiwan is supported by the Academia Sinica of Taiwan.
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Council for Science and Technology Policy (CSTP)UNSPECIFIED
Academia SinicaUNSPECIFIED
Subject Keywords:Metrology; CMOS sensor; multi-fiber, spectrograph, Schmidt telescope
Series Name:Proceedings of SPIE
Issue or Number:10702
Record Number:CaltechAUTHORS:20190102-155138003
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Official Citation:Shiang-Yu Wang, Richard C. Y. Chou, Pin-Jie Huang, Yin-Chang Chang, Hung-Hsu Ling, Chi-Hung Yan, Jennifer Karr, Shu-Fu Hsu, Hsin-Yo Chen, Yen-Shan Hu, James E. Gunn, Dan J. Reiley, Naoyuki Tamura, Naruhisa Takato, Yuki Moritani, Atsushi Shimono, "Metrology camera system of prime focus spectrograph for Subaru telescope," Proc. SPIE 10702, Ground-based and Airborne Instrumentation for Astronomy VII, 107027H (9 July 2018); doi: 10.1117/12.2311902
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92002
Deposited By: George Porter
Deposited On:03 Jan 2019 22:20
Last Modified:03 Oct 2019 20:40

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