Hyperion: Far-UV cross dispersion spectroscope design

Abstract

Hyperion is a far-UV mission that investigates the birth clouds of stars using a 40 cm aperture telescope feeding an imaging long-slit spectrometer. The science requirements of the mission dictate that the spectrometer covers 140.5-164.5 nm spectral range with resolution greater than 30,000. We employ smart and efficient design to create a long-slit, cross dispersed, echelle spectrometer that utilizes a two-mirror freeform imaging optics. Echelle spectra for n = -19, -18, and -17 over a 10 arcmin x 2.5 arcsec (length x width) FFOV are imaged onto the focal plane. We simulate the optical performance and the expected spectral efficiency.