@inproceedings{d36444149cca4a6ba152c349ee14857c,
title = "On-site precision heliostat metrology using starlight",
abstract = "This paper demonstrates a heliostat metrology system using starlight. Distant stars provide naturally well collimated light. By measuring the angular deviation of reflected starlight from different mirror regions, we can measure the slope on the heliostat surface and derive the shape. The method has been tested by measuring a star image formed by a heliostat with a single sheet float glass reflector measuring 2.4 m × 3.3 m and bent to form a focus at 113 m distance. A camera at the focus and imaging the heliostat was moved across a grid of points in the aberrated star image. Comparing the test results with the surface shape previously obtained from an indoor static screen deflectometry system, we find that the difference in the shape (with focus and astigmatism subtracted) is 91 μm, thus validating the proposed system. The corresponding difference in slope is below 1 mrad.",
keywords = "concentrating solar-thermal power, heliostat test, reflector metrology, starlight",
author = "Yiyang Huang and Roger Angel and Heejoo Choi and Matt Rademacher and Daewook Kim",
note = "Publisher Copyright: {\textcopyright} 2025 SPIE. All rights reserved.; Advances in Solar Energy: Heliostat Systems Design, Implementation, and Operation II ; Conference date: 05-08-2025 Through 06-08-2025",
year = "2025",
month = sep,
day = "18",
doi = "10.1117/12.3063036",
language = "English (US)",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
publisher = "SPIE",
editor = "David Haas and Marc Roger",
booktitle = "Advances in Solar Energy",
}