The AMiBA Hexapod Telescope Mount

TL;DR

This paper describes the design, control system, and performance verification of the AMiBA hexapod telescope mount, demonstrating its precision and suitability for radio astronomy observations.

Contribution

It introduces a novel hexapod mount for a large radio telescope, detailing its mechanical design, control system, and verified high-precision pointing capabilities.

Findings

Platform deformations less than 120 microns rms

Optical pointing error reduced to about 0.4 arcmin rms

Performance meets the specifications for the 7-element configuration

Abstract

AMiBA is the largest hexapod astronomical telescope in current operation. We present a description of this novel hexapod mount with its main mechanical components -- the support cone, universal joints, jack screws, and platform -- and outline the control system with the pointing model and the operating modes that are supported. The AMiBA hexapod mount performance is verified based on optical pointing tests and platform photogrammetry measurements. The photogrammetry results show that the deformations in the inner part of the platform are less than 120 micron rms. This is negligible for optical pointing corrections, radio alignment and radio phase errors for the currently operational 7-element compact configuration. The optical pointing error in azimuth and elevation is successively reduced by a series of corrections to about 0.4 arcmin rms which meets our goal for the 7-element target specifications.