Voyager's Infrared Spectrometer (IRIS) acts as three separate
instruments. First, it is a very sophisticated thermometer. It can
determine the distribution of heat energy a body is emitting, allowing
scientists to determine the temperature of that body or substance.
Second, the IRIS is a device that can determine when certain types of
elements or compounds are present in an atmosphere or on a surface.
Third, it uses a separate radiometer to measure the total amount of
sunlight reflected by a body at ultraviolet, visible, and infrared
The Voyager IRIS instrument obtained one thermal spectrum every
48 seconds (or "FDS count") throughout each planetary flyby.
The instrument was devoted primarily to atmospheric observations,
but it did acquire numerous thermal spectra of Saturn's ring system.
The IRIS Tabs
The tabs associated with this page describe the IRIS data files and
how to obtain them.
Instrument - Descriptive
information about the instrument.