The “ideal” spectrograph for atmospheric observations

Abstract. Spectroscopy of scattered sunlight in the near-UV to near-IR spectral ranges has proven be an extremely useful tool for analysis atmospheric trace gas distributions. A central parameter achievable sensitivity and spatial resolution spectroscopic instruments is étendue (product aperture angle entrance area) spectrograph, which at heart instrument. The instrument can enhanced by (1) upscaling all dimensions or (2) changing F number, (3) increasing area, (4) operating many (of identical design) parallel. (in principle) arbitrary factors options (4); effect limited. We present some new ideas considerations how determination gases could optimized using possibilities spectrograph design manufacturing. Particular emphasis on arrays massively parallel observations sunlight. Such reduce size weight orders magnitude while preserving light throughput. also discuss optimal individual spectrographs a array give examples systems use (low Earth orbit) satellite, including one with sub-kilometre ground pixel size.