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arXiv 1801.10596astro-ph.IM
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近红外多望远镜光束成像和制导方法

Methods for multiple telescope beam imaging and guiding in the near infrared

N. Anugu, A. Amorim, P. Gordo, F. Eisenhauer, O. Pfuhl, M. Haug, E. Wiezorrek, J. Lima, G. Perrin, W. Brandner, C. Straubmeier, J. -B. Le Bouquin, P. J. V Garcia

摘要:

大气湍流和任意两台望远镜之间的天体测量基线矢量的精确测量是相位参考干涉天体测量和成像的两个主要挑战。它们通过降低仪器灵敏度和天体测量精度以及由于不准确的相位而引入图像重建误差来限制光纤馈送干涉仪的性能。一个多光束采集和引导相机,以满足这些挑战,最近委托四光束组合器仪器,重力,在ESO甚大望远镜干涉仪。对于每个望远镜光束,它测量:a)通过对天空中的恒星进行成像来测量视场尖端倾斜; b)通过使用$2 \times 2$小透镜对安装在每个望远镜上的光瞳参考激光信标进行成像来测量望远镜光瞳偏移; c)使用$9 \times 9$ Shack-Hartmann的高阶像差。望远镜的瞳孔被成像,以便在观察时进行视觉监测。这些测量使得能够通过致动分别放置在光瞳和场平面中的倾斜镜的训练来进行主动场和光瞳引导。Shack-Hartmann测量的准静态像差用于聚焦辅助望远镜,并允许校正单位望远镜自适应光学系统和重力之间的非公共路径误差。这种引导使光注入单模光纤稳定,提高了灵敏度,减少了天体测量和图像重建误差。光束引导使得能够实现小于$50\,μ$的天体测量误差。本文介绍了多光束采集制导相机的数据处理方法、实验室试验及其在天空中的性能。

英文摘要:

Atmospheric turbulence and precise measurement of the astrometric baseline vector between any two telescopes are two major challenges in implementing phase referenced interferometric astrometry and imaging. They limit the performance of a fibre-fed interferometer by degrading the instrument sensitivity and astrometric measurements precision and by introducing image reconstruction errors due to inaccurate phases. A multiple beam acquisition and guiding camera was built to meet these challenges for a recently commissioned four beam combiner instrument, GRAVITY, at the ESO Very Large Telescope Interferometer. For each telescope beam it measures: a) field tip-tilts by imaging stars in the sky; b) telescope pupil shifts by imaging pupil reference laser beacons installed on each telescope using a $2 \times 2$ lenslet; c) higher order aberrations using a $9 \times 9$ Shack-Hartmann. The telescope pupils are imaged for a visual monitoring while observing. These measurements enable active field and pupil guiding by actuating a train of tip-tilt mirrors placed in the pupil and field planes, respectively. The Shack-Hartmann measured quasi-static aberrations are used to focus the Auxiliary Telescopes and allow the possibility of correcting the non-common path errors between the Unit Telescopes adaptive optics systems and GRAVITY. The guiding stabilizes light injection into single-mode fibres, increasing sensitivity and reducing the astrometric and image reconstruction errors. The beam guiding enables to achieve astrometric error less than $50\,μ$as. Here, we report on the data reduction methods and laboratory tests of the multiple beam acquisition and guiding camera and its performance on-sky.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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