MRI: Development of Enhanced Adaptive Optics System and Infrared Instrumentation for the Shane 3-meter Telescope

地面上的望远镜必须通过地球大气层的干扰来观测深空中的物体。当光穿过大气层时，由于风切变和大气层内温度和压力的变化，它会被湍流传播开来，这有效地降低了地面望远镜的分辨率。这一困难在很大程度上可以通过采用激光导星（LGS）和自适应光学（AO）的相对较新的技术来克服，其中明亮的激光照亮目标物体附近的一片天空。激光的光被上层大气中的钠原子吸收，然后再发射出去，而上层大气中有很多干扰的低层大气。然后，返回的信号可以用来跟踪光的随时间变化的大气畸变。自适应光学利用这些信息来快速调整望远镜仪器中的光学，以将图像恢复到（接近）从大气上方看到的图像。加州大学的利克天文台一直是天文学自适应光学技术发展的领导者。他们现在正在开发一种改进的系统，使用新的微机电系统（MEMS）技术，安装在Lick天文台的三米Shane望远镜上。这个新系统将极大地提高望远镜向仪器传送图像的清晰度。加州大学圣克鲁兹分校的Donald Gavel博士领导了这项工作。新的AO系统是由美国国家科学基金会通过其主要研究仪器计划资助的。

Telescopes on the ground must observe objects in deep space through the interference of the earth's atmosphere. As light passes through the atmosphere it gets spread out by turbulence due to wind shear and changes in temperature and pressure within the atmospheric layers which effectively diminishes the resolving power of earth-based telescopes. This difficulty can be overcome to a large extent by relatively new techniques employing Laser Guide Stars (LGS) and Adaptive Optics (AO) where a bright laser illuminates a patch of sky near the target object. The laser's light is absorbed and then re-emitted by sodium atoms in the upper atmosphere, above much of the interfering lower atmosphere. The return signal can then be used to track the time-dependent atmospheric distortion of the light. Adaptive Optics uses this information to rapidly adjust optics in the telescope's instrumentation to restore the image to (nearly) what would be seen from above the atmosphere. The University of California's Lick Observatory has been a leader in the development of adaptive optics techniques for astronomy. They are now developing an improved system using new micro-electrical mechanical systems (MEMS) technology to be installed on the Lick Observatory's three-meter Shane Telescope. This new system will very significantly improve the sharpness of the image delivered by the telescope to its instruments. Dr. Donald Gavel of the University of California-Santa Cruz is leading this effort. The new AO system is being funded by the National Science Foundation through its Major Research Instrumentation Program.