MRI: Development of a Deployable Tertiary Mirror for the Keck I Telescope

时间域观测将成为21世纪天体物理学的支柱。所有波长的广视场成像表明，宇宙是高度动态的，在所有时间尺度上都具有可变性。引起人们极大兴趣的是恒星爆炸、黑洞合并、日食行星、引力微透镜事件和耀斑来源，这些都源于一系列不同的天体物理过程。解决这些事件的天体物理学的核心是高精度的光谱和成像，理想情况下是在关键时刻和/或高节奏。这种观测需要使用大口径望远镜；但是，尽管望远镜可能拥有一套合适的仪器，但只有在每个观测之夜都能灵活和快速地使用这些仪器，才能获得时域天体物理学的科学回报。的确，越来越多的人需要宝贵的后续时间来利用世界？S最大的望远镜与经典的望远镜分配方式相冲突：一夜一仪。加州大学圣克鲁斯分校的杰森·普罗查斯卡试图为位于莫纳克亚顶的W.M.Keck天文台的直径10米的光学/红外Keck I望远镜解决这种情况，方法是用远程铰接镜取代手动定位的第三级镜，该镜能够在位于CASS焦点上的仪器和两个Nasmyth焦点中的任何一个之间快速(~2分钟)切换。与计划中的望远镜时间表变化相结合，这种技术上直接的修改不仅可以对天文事件(例如，超新星喷发、伽马射线爆发、行星撞击)做出快速反应，还可以更容易地进行节奏观测，处理有限访问的目标，并选择最佳利用特定夜晚-S天气条件的仪器和观测程序。这些进展将进一步提高几乎以任何标准衡量都是现代天文学家可用的最多产和最重要的设施之一的能力，并使其能够继续在理解时变宇宙方面发挥重要作用。NSF的天文科学部通过参与重大研究仪器计划，为开发和建造原型光谱仪提供资金。

Time-domain observations will serve as the backbone for 21st century astrophysics. Wide-field imaging at all wavelengths demonstrates that the universe is highly dynamic, with variability on all time-scales. Of great interest are exploding stars, black hole mergers, eclipsing planets, gravitational microlensing events, and flaring sources, which stem from a diverse set of astrophysical processes. Central to resolving the astrophysics of these events is high-precision spectroscopy and imaging, ideally at critical times and/or high cadence. Such observations demand the use of large-aperture telescopes; but while a telescope may possess a suite of suitable instrumentation, the scientific returns of time-domain astrophysics are only available if those instruments can be flexibly and rapidly accessed on each observing night. Indeed, the growing demands for precious follow-up time using the world?s largest telescopes conflicts with the classical approach of telescope allocation: one night, one instrument.Dr. Jason Prochaska of the University of California, Santa Cruz seeks to remedy this situation for the 10-m diameter optical/infrared Keck I telescope at the W. M. Keck Observatory atop Mauna Kea by replacing the manually positioned tertiary mirror with a remotely-articulated mirror capable of rapid (~2 minutes) switchover among the instruments that reside on the Cass focus and either of the two Nasmyth foci. When coupled with a planned change in telescope scheduling, this technologically straightforward modification will not only enable prompt response to astronomical events (e.g., supernova eruptions, gamma-ray bursts, planetary impacts), but also more easily permit cadence observing, address limited-access targets, and select the instrument and observing program which make best use of a particular night?s weather conditions. These developments will further enhance the capabilities of what is by virtually any measure one of the most productive and significant facilities available to modern-day astronomers, and allow it to continue to play a major role in understanding the time-variable universe.Funding for development and construction of the prototype spectrograph is being provided by NSF's Division of Astronomical Sciences through its participation in the Major Research Instrumentation program.