Clementine High-Resolution Camera (HIRES)

The HiRes camera combines a lightweight beryllium telescope with an image intensifier-coupled frame transfer CCD imager. Image shuttering is accomplished through voltage gating of the image intensifier. Maximum integration time is 733 milliseconds in 10.67 microsecond increments. Spectral response is limited in the system by the S-2 photocathode between 0.4 and 0.8 microns. Five spectral bands can be selected from a filter wheel which is controlled through the same SASI interface. A sixth filter position is allocated to an opaque filter for the image intensifier's protection.

The post-FPA electronics circuitry is identical to that used in the UVVIS camera. Images of the day side of the moon used intensifier gate times with relatively low gain settings on the order of 1 millisecond. Lifetime concerns about the photocathode and micro channel plates in the intensifier unit drove operational settings to low exposures. This resulted in photon shot noise significantly contributing to the overall noise in the HiRes sensor.