Ralph/LEISA - infrared spectrometer
LEISA is a wedged filter infra-red spectral imager that operates in a push-broom mode.
LEISA images a scene through a wedged filter (linear variable filter, Rosenberg et al., 1994) placed about 100 micrometers above a 256x256 pixel Mercury Cadmium Telluride (HgCdTe) detector array (a PICNIC array). An image is formed on both the wedged filter and the array simultaneously (there is less than 5% spectral broadening by the f/8.7 beam). LEISA forms a spectral map by scanning the FOV across the surface in a push broom fashion, similar to that of the MVIC TDI channels. The frame rate is synchronized to the rate of the scan, so that a frame is read out each time the image moves by the single pixel IFOV. The LVF is fabricated such that the wavelength varies along one dimension, the scan direction.
The LEISA description was was adapted from Reuter et al. (2007), Reuter et al. (2005) and the New Horizons website.
The Ralph/LEISA Tabs
The tabs associated with this page describe the Ralph/LEISA data files and how to obtain and use them.