Stereo-SCIDAR: optical turbulence profiling with high sensitivity using a modified SCIDAR instrument
Stereo-SCIDAR: optical turbulence profiling with high sensitivity using a modified SCIDAR instrument
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DOI：
10.1093/mnras/stt2150
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发表时间：
2013-12
影响因子：
4.8
通讯作者：
H. Shepherd;J. Osborn;R. Wilson;T. Butterley;R. Avila;V. Dhillon;T. Morris
中科院分区：
文献类型：
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作者：
H. Shepherd;J. Osborn;R. Wilson;T. Butterley;R. Avila;V. Dhillon;T. Morris
下一代自适应光学系统将需要层析重建技术来映射光学折射率波动，产生的大气湍流，沿沿着视线的天文目标。这些系统可以利用外部大气廓线仪提供的数据加以加强。这对于极大望远镜尺度的层析成像是重要的。在这里，我们提出了一种新的仪器，它利用广义闪烁探测和测距（SCIDAR）技术，使高灵敏度的大气光学湍流和风速廓线以上天文观测站的垂直廓线。新的方法，我们称之为“立体SCIDAR”，使用一个立体系统与闪烁图案从每个星星的双星星目标入射到一个单独的检测器。分离每个星星的光瞳图像具有几个优点，包括增加了目标恒星的星等差异容限;消除了由于通常与SCIDAR相关联的归一化误差而导致的重新校准的需要;交叉噪声的信噪比至少增加2倍，- 协方差函数，因此，对于等星等目标星的轮廓，对于3星等差异的目标，最多可提高16倍，并且更容易实时重建风-速度剖面理论响应函数计算的仪器，并使用Monte Carlo模拟的性能进行了研究。该技术是证明使用的数据记录在2.5米北欧光学望远镜和1.0米雅各布斯Kapteyn望远镜，无论是在拉帕尔马。
The next generation of adaptive optics systems will require tomographic reconstruction techniques to map the optical refractive index fluctuations, generated by the atmospheric turbulence, along the line of sight to the astronomical target. These systems can be enhanced with data from an external atmospheric profiler. This is important for Extremely Large Telescope scale tomography. Here we propose a new instrument which utilizes the generalized Scintillation Detection And Ranging (SCIDAR) technique to allow high sensitivity vertical profiles of the atmospheric optical turbulence and wind velocity profile above astronomical observatories. The new approach, which we refer to as ‘stereo-SCIDAR’, uses a stereoscopic system with the scintillation pattern from each star of a double-star target incident on a separate detector. Separating the pupil images for each star has several advantages including increased magnitude difference tolerance for the target stars; negating the need for re-calibration due to the normalization errors usually associated with SCIDAR; an increase of at least a factor of 2 in the signal-to-noise ratio of the cross-covariance function and hence the profile for equal magnitude target stars and up to a factor of 16 improvement for targets of 3 mag difference and easier real-time reconstruction of the wind-velocity profile. Theoretical response functions are calculated for the instrument, and the performance is investigated using a Monte Carlo simulation. The technique is demonstrated using data recorded at the 2.5-m Nordic Optical Telescope and the 1.0-m Jacobus Kapteyn Telescope, both on La Palma.