Detailed Design of a Deployable Tertiary Mirror for the Keck I Telescope

TL;DR

This paper details the design of a deployable tertiary mirror for the Keck I telescope, addressing challenges in opto-mechanical engineering to enable precise, repeatable deployment for time domain astronomy.

Contribution

It introduces a novel opto-mechanical design with an actuated swing arm and custom connections for the Keck I deployable tertiary mirror system.

Findings

Design successfully balances light path vignetting and system rigidity.

Prototype components developed for power, communication, and air supply.

System planned for commissioning in Spring 2017.

Abstract

Motivated by the ever increasing pursuit of science with the transient sky (dubbed Time Domain Astronomy or TDA), we are fabricating and will commission a new deployable tertiary mirror for the Keck I telescope (K1DM3) at the W.M. Keck Observatory. This paper presents the detailed design of K1DM3 with emphasis on the opto-mechanics. This project has presented several design challenges. Foremost are the competing requirements to avoid vignetting the light path when retracted against a sufficiently rigid system for high-precision and repeatable pointing. The design utilizes an actuated swing arm to retract the mirror or deploy it into a kinematic coupling. The K1DM3 project has also required the design and development of custom connections to provide power, communications, and compressed air to the system. This NSF-MRI funded project is planned to be commissioned in Spring 2017.