PLEXISS, a coronagraph for imaging the lunar atmosphere from the International Space Station

摘要

PLEXISS (Planetary Exospheres from the International Space Station) is a proposed small instrument dedicated to the coronagraphic imaging in the Na yellow doublet (5890 and 5896 A) and in the K red doublet (7665 and 7699) A of the transient lunar atmosphere from the International Space Station (ISS). The scientific return of PLEXISS can give important information for the understanding of the transient atmospheres of several other bodies of the Solar System; in particular, the European cornerstone mission Bepi-Colombo to planet Mercury can greatly benefit from PLEXISS. This paper describes the two concepts of coronagraphic telescope design (one totally reflecting and one totally refractive) we have developed for this very challenging application, that requires occulting the lunar disk and providing a clear field of approximately +-2° around it, with a resolution of about 30 arcsec per pixel.