ISPI Optical Design

The ISPI optical design originated with a design produced by Charles Harmer (NOAO) for the U. Florida IR camera FLAMINGOS [1]. This design was a close match to our science-defined specifications, was already optimized for the Mayall 4-m, and allowed cost savings by joint procurement of optics. Hence we adopted it for ISPI, with a slight reoptimization of element spacings for the Blanco telescope by Harmer and Maxime Boccas (CTIO).

This is a refractive, collimator-camera system with an intermediate cold pupil image. The f/3 camera employs one aspheric element; all other surfaces are spheres. Design performance is shown graphically below with spot diagrams (box size is 2x2pixels, ie. 36x36 microns)
The camera optics coupled to the Blanco 4-m give the following performance for 80% encircled energy diameter:

Note: The best and worst are not obtained respectively on axis and in the corner

The optics have been produced by Janos Technology, Inc [5]. The FLAMINGOS implementation has had first light [6] confimation of excellent image quality on Kitt Peak telescopes.

Ray Trace

March 22, 2004