Design and MAIT status of the UH2.2 adaptive secondary mirror

An adaptive secondary mirror (ASM) is currently being developed for the UH2.2 telescope, consisting of a slumped 620mm convex aspherical facesheet, manipulated by 210 variable-reluctance actuators and supported on a silicon aluminium alloy support structure. The total power dissipation of the actuators is expected to be under 3 Watts. The ASM will weigh around 55kg, which is about 15kg lighter than the original passive secondary mirror (M2). We present the design, breadboarding activities and manufacturing status of this adaptive mirror. The project is on track for delivery of the ASM in Hawaii in the middle of 2021.

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