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Armstrong, K. R.

Publications and source records attributed to Armstrong, K. R..

6 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Jupiter at five microns

The paper summarizes the information obtained in recent maps of Jupiter at 5 microns, a frequency at which the gases in Jupiter have a relatively low opacity. It is highly possible that 5-micron hot spots are breaks in the cloud deck permitting observation of the hot lower layers of the atmosphere. Many 5-micron sources coincide with blue visual features, but the details of the correspondence need further investigation. Large-scale changes in the appearance of the planet occur at 5 microns on time scales of months; these changes are sufficiently dramatic to produce detectable variations in the whole-disk flux from the planet. Their correspondence to large-scale changes in visual features is not yet determined.

Armstrong, K. R.↗
NASA NTRS1974

Far-infrared filters utilizing small particle scattering and antireflection coatings

High-transmission, low-pass scatter filters for blocking at wavelengths from 3.5 to 50 microns and single-layer antireflection coatings for optical materials used in the 25- to 300-micron region of the spectrum are described. The application of both techniques to liquid-He-cooled filters permits the construction of efficient low-pass and medium-width bandpass filters for use throughout the far infrared.

Armstrong, K. R.↗
NASA NTRS1973

New techniques for far-infrared filters.

The techniques considered make it possible to construct high performance low-pass wide-band, and medium-band filters at wavelengths in the range from 25 to 300 micrometers. Short wavelength rejection without appreciable loss at long wavelengths is achieved by means of small particle scattering. Spectral definition in the far infrared is obtained by cooling one or more crystalline materials to liquid-He or liquid-nitrogen temperatures. The problem of reflection losses at the various surfaces is solved by a new antireflection coating technique.

Armstrong, K. R.↗
NASA NTRS1973

Ground-based observations at 34 microns.

Filtering techniques for a new photometric band from 28 to 40 microns are described together with the results of ground-based observations of planets, stars, and galactic nebulae conducted with 28- and 61-in. telescopes in this wavelength interval. The data indicate that high angular resolution and good sensitivity can be obtained at 34 microns from the ground. Some stars have very cold (less than 100 K) circumstellar dust shells or clouds. The Kleinmann-Low nebula in M42 is extremely bright at 34 microns, whereas the Ney-Allen nebula associated with the Trapezium stars is much weaker.

Low, F. J.↗
NASA NTRS1972

Far-infrared brightness temperatures of the planets.

An airborne telescope operating in an altitude range from 45,000 to 50,000 feet together with a low-temperature germanium bolometer and six cooled filters were used in an investigation of the temperatures of the planets. The measurements conducted provide a basis for absolute calibration in the far infrared, confirm the high effective temperature and internal power of Jupiter, and give information on the far-infrared opacities and emissivities of the four bright planets.

Armstrong, K. R.↗