The Large Binocular Telescope main axis encoders: mounting hardware, read heads, and tape installation

S. Callahan; D. Ashby; T. Hair; J. Brynnel; S. Donovan; F. Dionies

doi:10.1117/12.670508

23 June 2006 The Large Binocular Telescope main axis encoders: mounting hardware, read heads, and tape installation

S. Callahan, D. Ashby, T. Hair, J. Brynnel, S. Donovan, F. Dionies

Proceedings Volume 6267, Ground-based and Airborne Telescopes; 62673B (2006) https://doi.org/10.1117/12.670508
Event: SPIE Astronomical Telescopes + Instrumentation, 2006, Orlando, Florida , United States

Abstract

The Large Binocular Telescope Observatory (LBT) encoded their elevation and azimuth axis with Farrand Inductosyn tape encoders. The authors present the unique design requirements to achieve high precision tracking and pointing. This paper describes the mechanical hardware used to meet these goals. The telescope elevation axis uses two tapes to encode 14m diameter tracks machined into the optical support structure. Each elevation tape is encoded with two custom read heads machined to fit the surfaces. The read heads are mounted on spring loaded flexures with rollers to insure consistent alignment of the heads to the tapes and to allow for radial run out. The azimuth is encoded with two tapes set end to end. Four custom read heads have been installed on similar flexures. The tape mounting hardware has been designed to maintain uniform and constant tension over the lifetime of the tape. We also describe the equipment and procedures used during installation to insure uniform tension of the tape in the track.

Citation Download Citation

S. Callahan, D. Ashby, T. Hair, J. Brynnel, S. Donovan, and F. Dionies "The Large Binocular Telescope main axis encoders: mounting hardware, read heads, and tape installation", Proc. SPIE 6267, Ground-based and Airborne Telescopes, 62673B (23 June 2006); https://doi.org/10.1117/12.670508

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