A ROCKET BORNE INFRARED HYGROMETER FOR THE MEASUREMENT OF WATER VAPOR
Abstract
A rocket borne infrared measuring instrument of the spectrometer type is described that, although specifically designed for the measurement of water vapor at high altitudes, could be adapted to the measurement of other absorbing gases in the atmosphere. The sun, near the horizon, is used as a source of infrared radiation for the spectrometer. The signal received at the absorption wavelength of 1.38 microns is compared with that received from a clear window of the atmosphere at 1.25 microns to form a differential signal that is telemetered to earth at various levels of sensitivity. In addition, the strength of the 1.25 micron reference signal is also telemetered as a measure of the illumination intensity. From the foregoing values the absorption of the atmosphere can be calculated as a function of altitude. A grating type spectrometer of the Ebert type is employed for the present instrument. The illumination system consists essentially of a spinning mirror that is adjusted in elevation by a simple search and 'lock on' procedure to illuminate the entrance slit of the spectrometer with pulses of light. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1962
- Accession Number
- AD0294833
Entities
People
- J. Leeder
Organizations
- Ballistic Research Laboratory