There is also a bulb command, for longer exposures, that allows the shutter to be held open for any desired length of time. The CCD has the performance characteristics outlined in Table. The CCD is mounted in a hermetically sealed package which is back-filled with argon. An operating temperature of around -35oC is needed for suppression of dark current and to minimize proton gamma and neutron radiation effects. The NC employs passive radiative cooling to maintain the detector operating temperature.
All wavelengths are in Angstroms.
The scanning mirror, located some distance forward of the camera lens faces 45 away from the camera viewing axis. Rotating the mirror about the camera axis at the proper rate enables comet tracking during flyby. The mechanism is a single DOF device. It requires proper spacecraft orientation so that the comet can be viewed in a viewing plane originating at the scan mirror and oriented perpendicular to the camera axis. The mirror's home position is at -20where the camera sees a black object on the spacecraft.