Thermal study of the LPSP instrument on OSO-I

The paper examines the very high spectral and spatial resolution spectroheliograph developed by the Laboratoire de Physique Stellaire et Planetaire for OSO-I. One of the chief problems associated with the instrument is that temperature changes and the gradients induced can affect the optical alignments by producing dimensional changes in the structural elements and by varying the curvature of the optical elements. The aim of the thermal study was to: (1) maintain temperatures in a reasonable range with a minimum of heat intensity, (2) minimize thermal gradients in the structure and optical elements, and (3) choose a strategy which would permit one to obtain the most predictable results.