Affiliation:
1. Hefei Normal University
2. Nanjing Institute of Astronomical Optics & Technology, Chinese Academy of Sciences
Abstract
The current cofocus maintenance strategy of the primary mirror of the
Large Sky Area Multi-Object Spectroscopic Telescope (Mb) using
Shack–Hartmann Wavefront Sensor (SHWFS) interrupts the observation
mission. This study proposed an Eddy current edge sensor with high
precision and accuracy to achieve closed-loop cofocus control. Through
structural design, interaction matrix deduction, installation
parameter analysis, and performance calibration, the edge sensor was
validated for use in detecting segment attitudes. The minimum cofocus
maintenance system comprising three segments was separated from Mb and
established to validate the effectiveness of the closed-loop cofocus
control with the novel edge sensor. The closed-loop control system was
effective within less than 1.5°C environmental temperature changes
after 13 h, which is considerably longer than the maintenance
time with the SHWFS. Moreover, continuous observation without
interruption is possible during one observation night.
Funder
Joint Fund of Astronomy
National Key Research and Development
Program of China