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  Sebring Mechanical Design, Inc.


Project: Redesign mounting brackets for optical telescope mirror segments
Client:University of Texas

The Hobby-Eberle Telescope (HET) is currently one of the world's largest optical telescopes, with an effective aperture of 9.2 meters and an 11 meter, hexagonal mirror array made from 91 segments. HET is part of the McDonald Observatory in Fort Davis, Texas.

The Hobby-Eberle Telescope
Hobby-Eberle Telescope on Mt. Fowles in the Davis Mountains 450 miles west of Austin, Texas. HET Web site.

The HET's individual mirror segments are interchangeable for servicing and polishing. Each mirror segment measures 1 meter across and weighs about 250 lbs. Each segment rests on a bracket that consists of three tetrahedral mounts and is computer controlled by an actuator at each of the mounting points.

Sebring Design worked with the original protoype of the mounting bracket to optimize the design, making the mount 25% lighter as well as stronger and more balanced. In addition, the final production design featured cost savings and improved manufacturability. Cost reducing methods included the use of investment castings and formed sheetmetal sections. Deliverables included CAD model and drawing files, bill of materials, and vendor quotations.

A similar mirror mount design was proposed for the Large Atacama Telescope (LAT) at Cornell University in New York. Sebring Design modified the original bracket design to incorporate twice as many tetrahedral mounts, providing additional support points to further reduce deflection of the mirror segments.

Project Portfolio

Mesa CV special procedures table
Pivot system for x-ray arm
Telescope mirror mount
X-ray support for C-Arm
Non-magnetic imaging chair
Antenna mast
Reed blade grinder
Mobile C-arm redesign
Tablet coating machine

CAD model of telescope mirror mount
CAD model of redesigned mirror mount. Image shows the mirror segment (blue) and the six tetrahedral mounts.
Photo of finished mirror mount used in Hobby-Eberle Telescope
Bracket with three tetrahedral mounts to support mirror segment. (Mirror segment not shown.)