|
Optical Systems:
The Ultraviolet Imager Optical system uses a high speed (f/2.9) three mirror off axis design resulting in a circular 8 degree full field of view. This design provides an unobscured optical aperture, excellent baffling, flat filed, provision for optical filter insertion and general compactness. Each of the three mirrors are portion of a conic section and all share a common optical axis. The mirrors made of aluminum which underwent an extensive thermal cycling, plating, machining, and polishing process. They are overcoated with a far ultraviolet reflective MgF2/Al coating. In order to minimize scattering, very smooth surfaces are required. The surface roughness achieved on these mirrors is less than 20 Angstroms rms. Internal baffling is incorporated to further reduce stray light scattering. The image surface is essentially flat over the 8 degrees diameter of the filed of view (an 18 mm diameter image plane).
For more information on the optical design of the UVI see the following paper:
- Johnson, R. B., 'Wide Field of View Three-Mirror Telescopes Having a Common Optical Axis', Opt. Eng., vol. 27, p. 1046, (1988).
- The optical design for the UVI was conceived by Barry Johnson. Refinements in the optical design were made by Drs. M. Krim and A. Nonemacher of Hughes Danbury. The final optical design was done by Dr. Chen Feng while at the Center for Applied Optics for the the University of Alabama in Huntsville.
Photographs: (Click images to view larger versions.)
3-D CAD rendering of the UVI optical design (22K)
The UVI Primary/Secondary mirror housing and internal baffling assembly (47K)
A view of the UVI optical bench side (195K)
A view of the UVI optical bench top (131K)
Back to UVI Instrument Description Main
|
