The camera-collimator lens  can contains a triplet with a large CaFl element in the center. Cargille 1160 oil is used to optically couple the three elements of the triplet. Oil was chosen over an optical glue such as Sylgard in order to allow flexibility later on, should the triplet need to be dismantled for some reason. Cargille 1160 was found to be UV transmissive, and unreactive to Sylgard and the rubber O-ring which seals the oil layers in the lens cells. At the top of the cells, a small pliable tube allows overflow relief.

Tests on a small triplet showed a voltaic reaction when plumbing hardware made of brass was used, which discolored the oil severely after a few months. We therefore fabricated pressure relief hardware out of aluminum and used teflon tape to isolate any non-aluminum hardware from contact with the oil.