<abstract xmlns="http://www.w3.org/1999/xhtml"><p>In the astronomical observation process of multi-object fiber spectroscopic telescope, the position measurement of fiber tips on the focal plane is difficult and critical, and is directly related to subsequent observation and ultimate data quality. The fibers should precisely align with the celestial target. Hence, the precise coordinates of the fiber tips are obligatory for tracking the celestial target. The accurate movement trajectories of the fiber tips on the focal surface of the telescope are the critical problem for the control of the fiber positioning mechanism. According to the special structure of the LAMOST telescope and the composition of the initial position error, this paper aims at developing a high precision and robust measurement method based on multiple iterations of bundle adjustment with a few control points. The measurement theory of the proposed methodology has been analyzed, and the measurement accuracy has been evaluated. The experimental results indicate that the new method is more accurate and more reliable than the polynomial fitting method. The maximum position error of the novel measurement algorithm of fiber tips with simulated and real data is 65.3 μm, and most of the position errors conform to the accuracy requirement (40 μm).</p></abstract>

In the astronomical observation process of multi-object fiber spectroscopic telescope, the position measurement of fiber tips on the focal plane is difficult and critical, and is directly related to subsequent observation and ultimate data quality. The fibers should precisely align with the celestial target. Hence, the precise coordinates of the fiber tips are obligatory for tracking the celestial target. The accurate movement trajectories of the fiber tips on the focal surface of the telescope are the critical problem for the control of the fiber positioning mechanism. According to the special structure of the LAMOST telescope and the composition of the initial position error, this paper aims at developing a high precision and robust measurement method based on multiple iterations of bundle adjustment with a few control points. The measurement theory of the proposed methodology has been analyzed, and the measurement accuracy has been evaluated. The experimental results indicate that the new method is more accurate and more reliable than the polynomial fitting method. The maximum position error of the novel measurement algorithm of fiber tips with simulated and real data is 65.3 μm, and most of the position errors conform to the accuracy requirement (40 μm).

Multiple Iterations of Bundle Adjustment for the Position Measurement of Fiber Tips on LAMOST

Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, 230027, Hefei, China

Experimental Center of Engineering and Material Sciences, University of Science and Technology of China, 230027, Hefei, China

Measurement Science Review

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

In the astronomical observation process of multi-object fiber spectroscopic telescope, the position measurement of fiber tips on the focal plane is difficult...

Multiple Iterations of Bundle Adjustment for the Position Measurement of Fiber Tips on LAMOST

Published Online: Aug 23, 2014

Page range: 190 - 197

Received: Nov 15, 2013

Accepted: Jul 29, 2014

DOI: https://doi.org/10.2478/msr-2014-0026

© by Yonggang Gu

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.