The Skylab X-Ray Spectroheliograph

On May 14, 1973, Skylab was placed in earth orbit by the National Aeronautics and Space Administration. The major scientific payload of this experimental space station is the Apollo Telescope Mount (ATM) which houses six major telescope instruments. As a group, these instruments are capable of observing the sun's radiation from X-rays to visible light. The Skylab program consists of three manned observing periods; the first period having a twenty-eight day duration, the second and third each having fifty-six days duration. These three observing periods are separated by unmanned periods of approximately forty days duration. From the data collected in these three observing periods, solar physicists will try to answer some of the basic questions concerning solar flares, solar activity, the heating of the solar corona and the solar cycle. The purpose of this paper is to give a brief description of the hardware and performance of one of these instruments, the X-ray spectroheliograph. The conceptual design of this instrument and scientific details of the subsystems have been discussed in Reference 2 as part of a general discussion on "Imaging in X-Ray Astronomy". A more extensive presentation of the instrument as a whole in the context of the goals in the solar physics area is in preparation (Reference 3).