Near-Infrared Tip-Tilt Sensor for Laser Guide Star Adaptive Optics

通过使用激光引导星星自适应光学系统，校正地球大气层对天文图像的影响的目标已经取得了相当大的成功，该系统提供了对分布在大型望远镜孔径上的湍流的定量测量。 然而，激光系统本身无法检测到由大气引起的物体图像中的系综偏移，并且如果进行这种校正，则衍射限制光斑中的环绕能量可以增加40%以上。 这样的“倾斜/倾斜”校正只能通过使用自然引导星星--一种包含在望远镜视场中的相当明亮的自然星星--与激光投影系统串联来实现。 Peter Wizinowich博士和加州天文学研究协会的合作者正在为位于夏威夷莫纳克亚山的凯克10米望远镜建造近红外倾斜传感器，这将实现这一目标。 通过在K（2.2微米波长）大气传输波段工作，计划中的系统将使用2弧分直径区域内的一到三颗星提供高带宽（高达1 kHz）倾斜/倾斜信息，并能够在整个视场内进行校正。 凯克望远镜可以说是世界上最先进、最可靠、最具科学生产力的大型天文望远镜系统。管理机构的科学家和技术人员是世界上最有能力的，山顶是一个杰出的观测地点。 通过各种方式，一般社区可以获得高达30%的观测时间，因此通过近红外倾斜/倾斜校正系统等机制改善望远镜的成像能力有利于所有美国天文学。 这项工作的资金由NSF的天文科学部通过其先进技术和仪器计划提供。

The goal of correcting the Earth's atmospheric effects on astronomical images has seen considerable success through the use of laser guide star adaptive optics (AO) systems that provide a quantitative measure of the turbulence distributed over the aperture of a large telescope. However, laser systems by themselves cannot detect the ensemble shift in an object's image that is induced by the atmosphere, and the encircled energy in a diffraction-limited spot could be increased by more than 40% if this correction were made. Such a "tip/tilt" correction is only available through the use of a natural guide star - a rather bright natural star included in the telescope field of view - in tandem with the laser projection system. The near-IR tip/tilt sensor being constructed by Dr. Peter Wizinowich and collaborators of the California Association for Research in Astronomy for the Keck 10-m telescope on Mauna Kea, Hawaii will accomplish this goal. By working in the K (2.2 micron wavelength) atmospheric transmission band, the planned system will provide high bandwidth (up to 1 kHz) tip/tilt information using one to three stars in a 2 arcminute diameter area, and enable corrections over that entire field of view. Additionally, focus corrections are available at a much higher time resolution than for standard schemes.The Keck telescopes are arguably the most advanced, reliable, and scientifically productive large-telescope AO systems available anywhere in the world. Scientists and technical staff at the managing institutions are among the most capable in the world, and the mountaintop is an outstanding observing site. Up to 30% of observing time is available to the general community through various means, so improvements in the imaging capabilities of the telescopes through mechanisms like near-IR tip/tilt correction systems benefit all of U.S. astronomy. Funding for this work is being provided by NSF's Division of Astronomical Sciences through its Advanced Technologies and Instrumentation program.