Studies of H Ly-α emissions in the solar neighborhood with the techniques of polarimetry and spatial heterodyne spectroscopy (SHS)

Ultraviolet astronomy is an important tool for the study of the interplanetary medium and diffuse, angularly extended emissions in planetary/comet atmospheres and their near space environments. We describe a new technique for high etendue observations of emission lines at R > 10 5 with an all-reflective spatial heterodyne spectrometer and polarmetric sampling of these lines with an ultraviolet optimized waveplate-Brewster mirror combination. The resulting system is themo-mechanically stable, has light collecting power substantially greater than HST for extended emissions, despite having a volume of several x 10 -3 m 3 . This makes the SHS polarimeter ideal for spacecraft applications. We describe the SHS and polarmetric optical techniques and provide a discussion of its planned development for studies of interplanetary hydrogen.