The optical design parameters of the long camera are described above. The long camera consists of lens elements mounted in bezels which are in turn mounted in a barrel assembly. The lenses must be removable for re-coating. The camera barrel is kinematically attached to the instrument mainframe, and includes features for alignment and removal/installation. The barrel assembly may be temperature controlled to minimize thermal stresses and changes in focus and scale. The camera barrel carries the focus mechanism, shutter, and filter changer.