Fabrication Challenges of Multi-focal-length Superachromatic Telescopes

There are many challenges associated with the design and construction of telescopes to have diffraction limited performance over the range from 400 to 900nm. The general applications of the system described are for television, film, and visual observation of objects from 300 meters to infinity with a 300mm aperture and focal lengths of 500, 1000, 2000, and 4000mm. The systems are designed to perform well at temperatures from -20 to 40 degrees Celsius and maintain high boresight stability when used as a tracking telescope. A sealed and purged instrument is essential for long term durability of the perforamnce. The figure shows the optical schematic of the system.