A computer-controlled infrared eclipse telescope

An f/8, chopped, dual beam, gyroscopically pointed telescope has been constructed for use in obtaining infrared (7-13 micro) observations of the spectrum of the thermal emission of the solar corona. The instrument employs a scanning Michelson interferometer with germanium beam splitter and a germanium bolometer operated at 2 K. A small general purpose digital computer is used for experiment control and data processing. The computer, using reference signals from the chopper, controls the position of the moving interferometer mirror (through a stepper motor), and the operation of an A/D converter enabling rapid measurements of the bolometer output to be made. Synchronous detection, necessary to minimize sky background radiation, is accomplished within the computer. The resulting interferograms are stored on magnetic tape for future processing and displayed on an x-y recorder. A fourier transformed spectrum may be generated on operator request in nearly real time.