Spectrometer system for diffuse extreme ultraviolet radiation.

A unique grazing incidence spectrometer system has been designed to study diffuse line emission between 80 and 650 A with 10-30 A resolution. The minimum detectable emission line strength during a 5-min observation ranges from 100-2000 ph cm(-2) sec(-1) str(-1). The instrument uses mechanically ruled reflection gratings placed in front of a linear array of mirrors. These mirrors focus the spectral image on microchannel plate detectors located behind thin filters. The field of view is 40 min of arc by 15 degrees , and there is no spatial imaging. This instrument has been fabricated, calibrated, and successfully flown on a sounding rocket to observe the astronomical background radiation.