FILTER WHEEL FOR POUR FILL DEWARS

This filter wheel can hold four filters, nominally 1 inch round up to 0.040 inch thick (with modifications it can accommodate thicker filters). The actuator to change filter positions is manual with a position indicator showing which filter is presently in position. The filter wheel is available in two back working distances, 1.3 inches and 2.5 inches, to accommodate different lenses.

With the filter wheel attached the (1.3 inch back working distance version) dewar is 206 mm high, 318 mm long, and 143 mm wide. Once cold (refill nitrogen after initial boil off) the dewar will hold at operating temperature for 10 hours if the FPA is not powered on, and for more than 6 hours if the FPA is powered on.