Paper
31 December 1980 Telescope Coalignment System For The Multiple Mirror Telescope(MroAT)
David McDonough
Author Affiliations +
Abstract
This paper describes the coalignment system for the six 1.8 m astronomical telescopes of the Multiple Mirror Telescope. Emphasis is on individual component alignment and the achievement and maintenance of particular image configurations. The system employs a HeNe laser as an artificial star with its light colli mated by a 0.7 m guide telescope and trasferred to the 1.8 m telescopes via periscopes and retroreflectors. Silicon detectors sense laser image position deviations due to mirror tilts or displacements, and generate signals to actively correct pointing errors via 3 axis motion of the tel Cassegrain secondaries. Procedures are given for aligning the laser beamsplitters, collimating the beams, and aligning the detectors sequentially to arrive at a desired configuration. Keys to the operation are the use of a pinhole in the guide telescope's focal plane as a defining point for the laser source, the active stabilization of the guide telescope's focus, the stability of the periscopes, and the use of remotely-controlled thin wedge prisms to change each laser beam's position when reconfiguring any one telescope. Tests of star tracking show typical coalignment to <1.0 arc second RMS. A discussion of problems encountered is included.
© (1980) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
David McDonough "Telescope Coalignment System For The Multiple Mirror Telescope(MroAT)", Proc. SPIE 0251, Optical Alignment I, (31 December 1980); https://doi.org/10.1117/12.959465
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KEYWORDS
Telescopes

Mirrors

Sensors

Prisms

Stars

Composites

Optical alignment

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