Measuring and Correcting Wind-Induced Pointing Errors of the Green Bank Telescope Using an Optical Quadrant Detector
Measuring and Correcting Wind-Induced Pointing Errors of the Green Bank Telescope Using an Optical Quadrant Detector
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DOI：
10.1086/660677
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发表时间：
2011-06-01
影响因子：
3.5
通讯作者：
Schwab, Frederic R.
中科院分区：
文献类型：
--
作者：
Ries, Paul;Hunter, Todd R.;Schwab, Frederic R.
风引起的指向误差是大口径高频射电望远镜的一个严重问题。在本文中，我们描述了一个光学象限探测器仪器，可以检测和提供一个校正信号的风引起的指向误差的100米直径的绿色银行望远镜（GBT）的实施。该仪器使用天文测量和计量学相结合的方法进行校准。我们发现，主要的风引起的指向误差的时间尺度上的分钟所造成的饲料臂被吹沿着风矢量的方向。我们还发现，风引起的结构激励几乎是不存在的。我们已经实施了离线软件，以应用指向校正的数据从成像仪器，如MUSTANG 3.3毫米测辐射热计阵列，它可以恢复类似的70%的灵敏度损失，由于风引起的指向错误。我们还进行了初步的测试，显示出很大的希望纠正这些指向错误在真实的时间使用望远镜的副反射器伺服系统结合象限探测器信号。
Wind-induced pointing errors are a serious concern for large-aperture high-frequency radio telescopes. In this paper, we describe the implementation of an optical quadrant detector instrument that can detect and provide a correction signal for wind-induced pointing errors on the 100 m diameter Green Bank Telescope (GBT). The instrument was calibrated using a combination of astronomical measurements and metrology. We find that the main wind-induced pointing errors on timescales of minutes are caused by the feed arm being blown along the direction of the wind vector. We also find that wind-induced structural excitation is virtually nonexistent. We have implemented offline software to apply pointing corrections to the data from imaging instruments such as the MUSTANG 3.3 mm bolometer array, which can recover similar to 70% of sensitivity lost due to wind-induced pointing errors. We have also performed preliminary tests that show great promise for correcting these pointing errors in real time using the telescope's subreflector servo system in combination with the quadrant detector signal.