Environmental testing of an all-reflective spatial heterodyne spectrometer for wide input angle measurements of H Ly-α at high spectral resolving power

Scattered solar and collisionally stimulated H Ly-alpha emission is a proven diagnostic for the study of the Sun, comets, the interplanetary medium, planet atmospheres, and corona. Here we discuss the construction and testing of a narrow bandpass instrument designed to observe H Ly-alpha emission at a resolving power of R similar to 100,000 from targets with an angular extent of <= 1/2 degree. The instrument is an all-reflective form of the spatial heterodyne spectrometer (SHS), a self-scanning Fourier Transform Spectrometer. It will be incorporated into the focal plane of a suborbital telescope that is scheduled for a March 2013 launch. Initial alignment and vibrational testing was performed with the instrument aligned to a visible analog line. The results showed alignment stability under vibration, but revealed several unacceptable resonances that have been corrected in the mechanical design.