Journal of Astronomy and Space Sciences (Dec 2001)
Manufacturing and Test Results of Off-Axis Parabolic Cylinder Mirror for FIMS
Abstract
Far-ultraviolet IMaging Spectrograph (FIMS) is the main payload of the first Korean scientific satellite, KAISTSAT-4, which will be launched in 2002. Among the optical parts, parabolic cylinder mirror does not have any heritage from previous astronomical missions, so the manufacturing and testing process itself is a challenging issue. We describe the method of manufacturing and measuring of the off-axis parabolic cylinder mirror and our initial experiments to establish the entire manufacturing process. Using the method, the profile error can meet the specification of ~λ per cm which is closely related with the astronomical performances. In case of the surface roughness, temperature controlled pitch polishing reduces Rq under 1 nm implying that scattering in the entire spectral range of FIMS is less than 2% of the incident UV light.