Variable Aperture Cold-Stop for Multiple f-number Optics

The DoD ranges have invested significant financial resources in optics, mainly long focal length telescopes for use in high speed cinematography with 35 mm and 70 mm film transport cameras. With the increased demand for long-range infrared imaging, the ranges are now beginning to in-vest in IR cameras. However, there exists a fundamental incompatibility between IR imaging and telescope optics. OKSI has demonstrated a patent-pending solution whereby a variable cold stop is introduced into the camera to match its aperture to that of the telescope. An additional re-lay optical assembly is used to project the telescope aperture-stop onto this camera's cold stop, thus eliminating the problems associated with parasitic radiation that degrade the imagery. The technology will allow using an IR camera prices in the range of $50K to $100K with any telescope using a $10K optical relay, instead of investing in multiple cameras, one for each tele-scope. Under the proposed Phase-II, WSMR will receive a high-speed, large format MWIR camera sys-tem configured with OKSI's variable cold stop and the associated optics for (i) wide field of view operations using refractive optics, and for (ii) narrow field of view operations using range telescopes. This system will be tested and demonstrated to work with a large aperture, long focal length telescope at WSMR. Further development will explore the adaptation of the camera to various types of telescopes.