van Dam Marcos A, McLeod Brian A, Bouchez Antonin H
Appl Opt. 2016 Jan 20;55(3):539-47. doi: 10.1364/AO.55.000539.
The Giant Magellan Telescope (GMT) consists of seven 8.365 m segments, with gaps of 0.345 m between adjacent segments. A unique challenge for GMT lies in phasing the segments and, in particular, how to measure segment piston optically while the telescope is in science operation. In this paper, we present a dispersed fringe sensor (DFS) to make these measurements using a novel algorithm. We show that using four off-axis DFSs operating at J-band with 10 ms exposures, we are able to measure segment piston to the required 50 nm accuracy every 30 s with over 90% sky coverage.
巨型麦哲伦望远镜（GMT）由七个8.365米的镜段组成，相邻镜段之间的间隙为0.345米。GMT面临的一个独特挑战在于镜段的相位调整，特别是在望远镜进行科学观测时如何通过光学手段测量镜段的活塞位移。在本文中，我们提出了一种色散条纹传感器（DFS），并使用一种新颖的算法进行这些测量。我们表明，使用四个在J波段工作、曝光时间为10毫秒的离轴DFS，我们能够每30秒以超过90%的天空覆盖率将镜段活塞位移测量到所需的50纳米精度。
