An interferometer comprising a base forming an interior, and first and second optical members located in the interior of the base. The interferometer further comprises a first retainer assembly connecting the first optical member to the base, translation means for moving the second optical member relative the first optical member to vary the distance between the first and second optical members, and a second retainer assembly connecting the second optical member to the translation means. The preferred mechanical configuration and design features of the interferometer produce a very durable instrument that can rapidly scan and accurately filter light across a wide bandwidth. This uniquely designed instrument combines high speed switching, high resolution, wide bandwidth, and adjustable damping capabilities in a durable flight capable instrument.