Infrared spectrometer for Voyager.

The Voyager IR investigation uses a Michelson interferometer with a 4.3-cm(-1) spectral resolution in the 80-2500-cm(-1) range and a single-channel radiometer for the visible and near-IR, 5000-30,000-cm(-1). Both devices share a Cassegrain telescope with a 50-cm diam primary mirror and a 0.25 degrees field of view. Design, calibration, and performance are discussed along with a sample spectrum of Jupiter.

Mariner 9 michelson interferometer.

The Michelson interferometer on Mariner 9 measures the thermal emission spectrum of Mars between 200 cm(-1) and 2000 cm(-1) (between 5 microm and 50 microm) with a spectral resolution of 2.4 cm(-1) in the apodized mode. A noise equivalent radiance of 0.5 x 10(-7) W cm(-2) sr(-1)/cm(-1) is deduced from data recorded in orbit around Mars. The Mariner interferometer deviates in design from the Nimbus 3 and 4 interferometers in several areas, notably, by a cesium iodide beam splitter and certain aspects of the digital information processing. Special attention has been given to the problem of external vibration. The instrument performance is demonstrated by calibration data and samples of Mars spectra.

Nimbus 4 michelson interferometer.

The Michelson interferometer, IRIS-D, flown on Nimbus 4 in April 1970 is an improved version of the interferometer, IRIS-B, flown on Nimbus 3 a year earlier. Thermal emission spectra of the earth are being recorded between 400 cm(-1) and 1600 cm(-1) with a nominal spectral resolution of 2.8 cm(-1) and a noise equivalent radiance between approximately 0.5 and 1 erg sec(-1) cm(-2) ster(-1) cm. This paper describes the design and performance of the IRIS-D and concentrates on the design differences that exist between the interferometers flown on Nimbus 3 and 4. The performance is demonstrated by examples of spectra obtained while in earth orbit.