The Extreme Ultraviolet Spectrograph

The EUV instrument is a one-dimensional imaging spectrograph that views a vertical wedge of the sky. Using the spacecraft motion, it forms a two-dimensional image of the sky as this wedge moves horizontally in a "push-broom" configuration. 

This EUV instrument design is based on the heritage of four UCB “EURD-class” astrophysical space flight instruments (see top picture). These astrophysical instruments were designed for detecting similar ultra-violet wavelengths as the EUV instrument, but for signals that are an order of magnitude less bright than the Earth’s airglow. The interpretation of the EUV dayglow builds on the recent success of the DMSP-SSULI and RAIDS instruments.