Multi-Spectral Solar Telescope Array

Abstract

The development of multilayer optics has profound implications for soft x-ray/extreme ultraviolet (XUV) astronomy. During the October 1987 flight of the Stanford/Marshall Space Flight Center Rocket X-Ray Spectroheliograph, narrow wavelength band, low scatter soft x-ray/extreme ultraviolet spectroheliograms were obtained with -1 arcsec spatial resolution at X - 173 A (Fe IX, Fe X) and at is. - 256 A (He II Ly-3). Although the Cassegrain telescopes used in this experiment were small (63.5 mm diameter) and utilized spherical rather than paraboloidal/hyperboloidal mirrors, the images produced exceed in quality any XUV spectroheliograms previously obtained with either normal or grazing incidence techniques. We describe a new rocket spectroheliograph instrument, the Multi- Spectral Solar Telescope Array (MSSTA), that is currently being prepared for launch in August 1990. This instrumentwill utilizetrue Ritchey-Chrétien optics of 127 mm diameter and parabolic Herschelian optics of 40 mm diameter, which will allow spectroheliograms to be obtained over the soft x-ray/extreme ultraviolet/far ultraviolet spectral range (40 to 1550 A). The performance of this new instrument should definitely demonstrate the unique combination of ultrahigh spatial resolution and spectral differentiation that multilayer optics afford for astronomical observations. The MSSTA will also represent the first astronomical use of an important new optical device, the multilayer grating. The MSSTA should obtain unprecedented information regarding the structure and dynamics of the solar atmosphere in the temperature range i04 to i07 K.