Refractive static Fourier transform spectrometer: a balloon borne application

Static Fourier Transform spectrometers are traditionally realized with reflecting diffractive gratings. The positive aspects of these instruments, wide field of view and the absence of moving parts, are tested on an optical configuration in which the diffractive-reflective gratings are replaced with refractive-reflective prisms (Littrow prisms).Beside the reduction in the resolution power, especially in the near IR, due to the dispersive power of the glasses, the optical quality of Littrow prisms can provide low noise instruments at low price.The application to a sounding balloon flight on the Hemera project is presented. The flight took place in October 2021 at the CNES "Centre d'Opérations Ballons" at Aire sur l'Adour, France.This work has been supported by ASI, Agenzia Spaziale Italiana, Agreement n. 2019-33-HH.0. for the payload realization and the flight opportunity has been provided by the European Commission in the frame of the INFRAIA grant 730790-HEMERA.