Measuring the absolute height and profile of the mesospheric sodium layer using a continuous wave laser
Measuring the absolute height and profile of the mesospheric sodium layer using a continuous wave laser
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使用连续波激光测量中间层钠层的绝对高度和轮廓
DOI：
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发表时间：
2003
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通讯作者：
O. GmbH
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文献类型：
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作者：
D. Butler;R. Davies;R. Redfern;N. Ageorges;H. F. Mpia;Heidelberg;H Germany;Mpe;Garching;N. U. Ireland;Galway.;Ireland;E. Observatory;Marconi Communications;O. GmbH
我们开发并测试了一种基于激光雷达的新方法，利用连续波激光测量介观球面钠层的高度和轮廓。它比经典的激光雷达有50%的时间是开启的，因此原则上可以用于激光导星自适应光学观测。与直接成像技术相比，它也具有显著的优势，因为它不需要第二个望远镜，几乎不受大气条件的影响，并且避免了在确定高度时的三角测量问题。从长远来看，使用这种方法的定期监测将允许建立一个关于钠层剖面、高度和返回通量测量的有价值的数据库，这将使天文台天文学家能够以最佳方式安排观测。在本文中，我们描述了在西班牙卡拉阿尔托天文台使用阿尔法激光导星系统进行的原始实验。我们通过将激光雷达的结果与辅助望远镜同时成像的结果进行比较来验证该方法。给出了将在甚大望远镜激光导星设备中实施的类似系统的模型，该系统将能够在1分钟的时间尺度上以小于200米的精度确定自适应光学系统的初始聚焦设置。
We have developed and tested a novel method, based on LIDAR, of measuring the height and profile of the meso- spheric sodium layer using a continuous wave laser. It is more ecient than classical LIDAR as the laser is on for 50% of the time, and so can in principle be used during laser guide star adaptive optics observations. It also has significant advantages over direct imaging techniques because it does not require a second telescope, is almost independent of the atmospheric conditions, and avoids triangulation problems in determining the height. In the long term, regular monitoring using this method would allow a valuable database of sodium layer profiles, heights, and return flux measurements to be built up which would enable observatory sta astronomers to schedule observations optimally. In this paper we describe the original experiment carried out using the ALFA laser guide star system at Calar Alto Observatory in Spain. We validate the method by comparing the LIDAR results with those obtained from simultaneous imaging from an auxiliary telescope. Models are presented of a similar system to be implemented in the Very Large Telescope Laser Guide Star Facility, which will enable the initial focus setting for the adaptive optics systems to be determined with an accuracy of less than 200 m on a timescale of 1 min.