快速变化波前对高帧频天文成像影响的研究

To meet the needs of ground-based high angular resolution astronomical imaging technology development, we want to investigate the characteristic of a sequence of high frame-rate short-exposure images changing when fast variation occur on atmospheric turbulence distorted wavefront, by the purpose of discovering time-domain properties of high frame-rate short-exposure imaging and properties of the best images selecting from a sequence of short-exposure frames. To establish simulation model of random phase-changing screen passing across telescope aperture driving by wind speed as a diagnostic tool, we will assess the match between modeling and observation to analyzing the properties of high frame-rate short-exposure imaging under specific seeing conditions on short timescales, and to get more accurate observational parameters and probability of the best short-exposure frames been selected. The feature and novelty of our research is putting wind speed into analyzing as an important observational parameter, and also obtaining short-exposure images and atmospheric turbulence characteristics on the same optical path as imaging simultaneously by utilizing AO system. Conclusion of this research will be the basis to improve the observation efficiency by according them to adjust imaging system control parameters during observations and observing strategy making. Besides meeting the requirements of data processing and processing methods research, the results should be beneficial to develop the seeing monitoring technology and the ground-based high angular resolution astronomical imaging technology including adaptive optics.

本项目从地基光学高分辨天文成像技术研究需求出发，针对高帧频短曝光天文图像序列在湍流畸变波前快速变化时的成像特性展开研究，分析其时域特性以及在序列短曝光图像中的数据帧优选特性。研究内容拟通过建立随机相位屏风速仿真数值模型作为分析工具，将仿真计算结果与实测数据进行匹配对比，研究特定视宁度参数条件下高帧频短曝光图像序列在较小时间范围内的成像特性，获取更准确的视宁度参数以及该参数下的数据帧优选概率。引入风速条件作为重要观测参数，并利用自适应光学系统在成像同时获取相同光路上的湍流畸变波前特征进行分析是本项目研究特色。研究结果是实测过程中系统控制参数调整和制定观测策略以提高观测效率的重要依据；在满足观测数据处理及其方法研究的同时，有益于包括自适应光学在内的地基高分辨天文成像技术和视宁度监测技术的发展。

项目研究立足于地基光学观测的数据处理需求，为有效处理高帧频短曝光观测数据，针对视宁度这一观测条件的快速变化时域特性进行研究。以便为更优的短曝光高分辨成像观测策略和数据处理方法研究提供支持。研究内容包括短曝光成像数值仿真系统的建立；以及基于依托观测设备，建立一套可同时获取相同光路上的湍流畸变波前和高帧频短曝光目标图像的实验系统。以期通过将仿真计算结果与实测数据进行匹配对比，研究特定视宁度参数条件下高帧频短曝光图像序列在较小时间范围内的成像特性。项目研究建立的湍流大气成像数值仿真系统作为地基天文光学观测分析工具，在满足高帧频短曝光数据处理及其方法研究的同时，也可用于包括自适应光学在内的地基高分辨天文成像技术和视宁度监测技术研究的分析工具，对目前高时间分辨率下的天文观测方法研究有重要意义。