Instrument Description

• The filter wheel mechanism's purpose is to position the commanded filter in the optical path. The mechanism uses a dual winding, permanent magnet, mu-metal shielded stepper motor with a harmonic drive output. Discrete encoders to identify filter wheel positions are mounted on the same structure as the motor. These include optical fiducials and micro switches.
• The folding mirror mechanism's purpose is to position a mirror in the optical path so that an image is either incident on the primary detector or reflected onto the secondary detector. A push-push mechanism mounted on the output of a paraffin actuator is used to toggle the spring loaded mirror between two positions.
• The aperture door mechanism's purpose is to open and close the aperture door. A push-push mechanism mounted on the output of a paraffin actuator is used to toggle the spring loaded aperture door between two positions. Optical fiducial encoders and discrete microswitches are used to determine the door's position.
• The mechanisms were designed by Dr. Anees Ahmad of the Center for Applied Optics at the University of Alabama in Huntsville, and George Loughhead. The assembly and testing of the mechanisms was performed by Chuck Fellows and Larry Savage. The manufacturer of the stepper motor is Schaeffer Magnetics, Inc., of Chatsworth, CA. The manufacturer of the paraffin actuators is Starsys Research, Boulder, CO.

Photographs: (Click images to view larger versions.)

The UVI filter wheel motor and primary mirror (83K)
The UVI folding mirror mechanism assembly (83K)
The UVI aperture door mechanism assembly (85K)