Monitoring Venus cloud top: the VenSpec-U spectrometer on board ESA EnVision [post]

Emmanuel Marcq, Gabriel Guignan, Benjamin Lustrement, Franck Montmessin, Jérémie Lasue, Bruno Bézard, Ann Carine Vandaele, Jörn Helbert, Thomas Widemann, Colin Wilson, Richard Ghail
2020 unpublished
Instrument description The VenSpec-U instrument is a dual channel UV spectral imager (low and high spectral resolution channels, "LR" and "HR" hereafter), part of the VenSpec spectrometer suite on board the proposed Venus orbiter EnVision. Each channel consists of an entrance baffle, an objective composed of two lenses and a stop diaphragm, and a spectrometer composed of a slit and a toroidal holographic grating. It also includes s shortpass filter to reject the wavelengths above the higher
more » ... t of both channel bands and a zero-order trap to avoid straylight due to internal reflexions of the grating zeroorder. The optical layout is presented in Figure 1 . Both LR and HR slits are parallel and the optical layout is such that both channels have the same instantaneous field of view (FoV), allowing simultaneous observations and calibrations. Each slit image is then spectrally dispersed by its respective toroidal holographic grating and is formed on a shared CMOS back-side illuminated detector. Figure 1: VenSpec-U optical layout overview, with the HR and LR channels respectively on the left and on the right.
doi:10.5194/epsc2020-622 fatcat:iqi4lx3uxffrpixhwae6aga5c4