Title of Paper: Very Wide Field of View Imaging Spectrometer

Principal Author: Randy Pollock

Abstract: The two primary applications for terrestrial imaging spectrometry from space are atmosphere measurements (such as TOMS and AIRS) and surface characterization (such as EO-1 and OrbView-4). Atmospheric instruments require a very wide swath and have traditionally used rotating scanners to provide cross-track information. This approach reduces integration times (and thus signal to noise) substantially. Surface instruments tend to be pushbroominstruments to provide better signal to noise, but struggle to provide a swath wider than several degrees.

The Wide Field-of-View Imaging Spectrometer (WFIS) is a patented, all-reflective design that provides relatively fast (< f/3) optics coupled with a variable swath of up to > 120 degrees cross track. Since the WFIS design is all-reflective, it is possible to adapt this instrument to applications in the UV and IR with minimal design changes.

A 70-degree field of view version is operating in the laboratory; a 120-degree field of view version is currently being developed under NASA's Instrument Incubator Program. The latter instrument compatible with aircraft flights and is being built to space-flight standards. Both versions operate in visible light and provide spectral resolution finer than 2 nm from 360 to 1,000 nm.

This paper provides an overview of the design, assembly and performance of the WFIS instruments.