TIROS-3 Medium-Resolution Scanning Radiometer Level 1 Final Meteorological Radiation Data (FMRT) product contains radiances expressed in five infrared/visible wavelength regions, expressed in either equivalent blackbody temperature (IR channels 1, 2 and 4) or effective radiant emmitance (visible channels 3 and 5). The data will trace an elliptical, parabolic, or hyperbolic pattern on the ground due to the rotating of the instrument about the satellite spin axis. There is one orbit per file. The data were originally written on IBM 7094 machines, and these have been recovered from magnetic tapes, referred to as the Final Meteorological Radiation Tapes (FMRT). The data are archived in their original IBM 36-bit word proprietary format, also referred to as a binary TAP file. The TIROS-3 satellite was successfully launched on July 12, 1961. The Medium-Resolution Scanning Radiometer experiment returned data for about two and a half months. A previous instrument flew on TIROS-2 and two follow-on instruments were flown on TIROS-4 and -7. Response characteristics of all channels degraded rapidly after launch. The greatest uncertainty in the radiation measurements is due to the apparent shift in the zero radiation level. Data are usable for channels 1, 2, 3, 4, and 5 up to orbits 118, 875, 875, 130 and 300, respectively. The instrument is a five channel radiometer with a 55 km footprint at nadir with the following characteristics: Channel 1: 6.0 to 6.5 microns - water vapor absorption Channel 2: 8.0 to 12.0 microns - atmospheric window Channel 3: 0.2 to 6.0 microns - reflected solar radiation Channel 4: 8.0 to 30 - terrestial radiation Channel 5: 0.55 to 0.75 microns - response to the TV system The Principal Investigator for these data was Joseph D. Barksdale from NASA Goddard Space Flight Center. This product was previously available from the NSSDC with the identifier ESAD-00141 (old id 61-017A-03A).