Abstract: A mounting mechanism is provided for aligning and securing an optical instrument to a platform. The mechanism includes a housing, a trunnion and a base-plate. The housing receives the optical instrument along a longitudinal axis. The housing includes an attach support for the optical instrument, and an interface having vertically-facing cylindrical-fastener orifices. The trunnion supports the housing at the interface. The trunnion has pluralities of vertical slots and horizontal slots. Each vertical slot overlaps a corresponding vertical orifice. The vertical slots provide elevation displacement to vertically translate and pitch the housing. The horizontal slots provide lateral displacement to horizontally translate and yaw the housing. The base-plate supports the trunnion and is mountable onto the platform. The base-plate has a plurality of horizontally-facing cylindrical-fastener orifices. Each horizontal slot on the trunnion overlaps a corresponding horizontal orifice on the base-plate.