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.