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At least 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Economical phased-array antenna for environmental applications

Antenna system handles data acquisition and tracking, functions as a sensitive radio telescope, and serves as a radiometer in earth atmosphere investigations. Antenna's sensitivity permits resolution of solar disk quadrants in Doppler radar observations. Antenna also serves as a planetary radar device and link to commercial aircraft.

Higgins, W. T.↗
NASA NTRS1970

Loft test model

Dynamic structural analysis on low frequency radio telescope scale model with paraboloidal antenna

Hibbard, W. D.↗
NASA NTRS1972

Planetary observations at millimeter wavelengths

Observations of the Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn were made at 3.1 mm and 8.6 mm wavelengths with a 16-foot radio telescope between March and August, 1971. Absolute brightness temperature data are given. All errors are one standard deviation and include uncertainties in antenna gain calibration. The solar and lunar temperatures are in excellent agreement with published observations. The planetary measurements at 3.1 mm are consistently higher than previous results. The implications of higher temperatures with respect to existing atmospheric and surface models are discussed.

Ulich, B. L.↗
NASA NTRS1971

Solar radio emission at 1.2 mm wavelength.

A 36-ft radio telescope was used in the investigations. The 1.2 mm wavelength receiver connected to the telescope is a helium-cooled germanium bolometer. The 1.2 mm solar maps were obtained by scanning the sun in right ascension at the rate of 1 deg per minute. A temperature of 6000 K was assumed for the 1.2 mm quiet sun temperature for all solar maps. Eight maps at 1.2 mm were obtained on six different days. The 1.2 mm regions are rather large and without much structure; they are closely associated with Ca-plage regions.

Kundu, M. R.↗
NASA NTRS1972

New horizons in astronomy.

Besides the study of astronomy itself, other topics included cover the geological and biological developments on earth and basic physics of matter, heat, and light. Optical and radio telescopes are discussed, as well as photographic and photoelectric means of detection. The immediate solar system is described by topics on the properties and atmospheres of the inner and outer planets, the sun's energy, sunspots, and the solar spectrum. Stars both on and off the main sequence are discussed in terms of distances, intrinsic properties, lifetimes and evolution. The Milky Way is compared to other galaxies in size, star population and structure, and the different galaxy shapes are pictured. Topics of most recent interest are covered by results of the lunar explorations, new concepts of Mars, and problems of space travel. Problems of modern astronomy include pulsars, neutron stars, and quasars.

Brandt, J. C.↗
NASA NTRS1973

Life beyond earth and the mind of man

A symposium is reported on the implications of the possibility of extraterrestrial life for social, philosophical, and humanistic impacts. The viewpoints from astronomers, biologists, physicists, anthropologists, and theologians are given. Costs involved for finding this life are discussed along with the possible benefits to society. The direct implications from radio telescopes, the Pioneer 10 plaque, and discussions between the panelists are also reported.

Berendzen, R.↗
NASA NTRS1973

Observations of Jupiter at 13-cm wavelength during 1969 and 1971.

Radio observations of Jupiter have been carried out at Goldstone, CA at a wavelength of 13 cm during the oppositions of 1969 and 1971. In 1969, circular-polarization and total-flux measurements were made with a 64-m radio telescope. From May through October 1971, Jupiter's flux density was measured at weekly intervals with a 26-m antenna. The upper limit to the degree of circular polarization over the longitude ranges 10-100 deg and 160-250 deg System III (1957.0) is 1%; the flux data have been used to derive a magnetospheric rotation period which is approximately 0.37 sec longer than the IAU System III (1957.0). The flux-density data define beaming curves which are apparently different from 11-cm beaming curves measured in 1964. Jupiter's peak flux density decreased by 20% between 1964 and 1971, and 8% between 1969 and 1971.

Gulkis, S.↗
NASA NTRS1972

Remote sensing of atmospheric and surface temperatures with microwaves.

Solids, liquids, and gases emit at microwave wavelengths measurable amounts of black-body thermal radiation. Receiver sensitivities readily approach 0.01 K, and permit accurate measurements of land, sea, and atmospheric temperatures. Sea and land temperature measurements must be corrected for the effects of surface emissivity, but these effects can often be measured or estimated. Observations near the 5 mm wavelength 02 resonances can yield atmospheric temperature profiles with an approximate accuracy of 2 K for altitudes 0-80 km. Such measurements from balloons and aircraft suggest that the planned earth-orbital satellite experiments will yield data valuable for numerical weather prediction. Ground-based radio telescopes and planetary-probes have yielded similar information about the surfaces and atmospheres of other planets.

Staelin, D. H.↗
NASA NTRS1973

NASA directory of observation station locations, volume 1

Geodetic information for NASA tracking stations and for observation stations cooperating in NASA geodetic satellite programs is presented. A Geodetic Data Sheet is provided for each station, giving the position of the station and describing briefly how it was established. Geodetic positions and geocentric coordinates of these stations are tabulated on local or major geodetic datums and on selected world geodetic systems. The principal tracking facilities used by NASA, including the Spaceflight Tracking and Data Network, the Deep Space Network, and several large radio telescopes are discussed. Positions of these facilities are tabulated on their local or national datums, the Mercury Spheroid 1960, the Modified Mercury Datum 1968, and the Spaceflight Tracking and Data Network System. Observation stations in the NASA Geodetic Satellites Program are included along with stations participating in the National Geodetic Satellite Program. Positions of these facilities are given on local or preferred major datums, and on the Modified Mercury Datum 1968.

Source record↗
NASA NTRS1974

Polarimetric observations of Comet Kohoutek (1973f)

Radio, optical, and visual observations were made of Comet Kohoutek (1973f) using facilities of the National Radio Astronomy Observatory (NRAO) and of the Hawaii Night Sky Observatory, State University of New York at Albany (SUNYA). Transit observations were made using the NRAO 300 ft radio telescope on six consecutive days beginning November 24, 1973. Observations were carried out in the continuum at 11 cm using the 4-feed system at different position angles. The data were recorded on magnetic tape and were computer reduced. Results were negative, with an rms error of 62 milli flux units, giving an upper limit of 180 mfu for the 11 cm continuum emission from the Comet. This relatively high detection limit resulted from a combination of interference and bad weather that affected these pre-perihelion observations. No observations could be scheduled near or after perihelion.

Weinberg, J. L.↗
NASA NTRS1974

Sensitivity of Josephson-effect millimeter-wave radiometer

The noise temperature and the minimum detectable temperature of a Josephson junction in video detection of microwave and millimeter-wave radiation has been calculated. We use the well-known method based on a Fokker-Planck equation. The noise temperature can be very close to ambient temperature. Because its predetection bandwidth is very wide, a Josephson-effect radio telescope receiver can have a minimum detectable temperature better than that of a traveling-wave maser.

Ohta, H.↗
NASA NTRS1974

Absolute brightness temperature measurements at 2.1-mm wavelength

Absolute measurements of the brightness temperatures of the Sun, new Moon, Venus, Mars, Jupiter, Saturn, and Uranus, and of the flux density of DR21 at 2.1-mm wavelength are reported. Relative measurements at 3.5-mm wavelength are also preented which resolve the absolute calibration discrepancy between The University of Texas 16-ft radio telescope and the Aerospace Corporation 15-ft antenna. The use of the bright planets and DR21 as absolute calibration sources at millimeter wavelengths is discussed in the light of recent observations.

Ulich, B. L.↗
NASA NTRS1974

CO and CS in the Orion Nebula

The reported observations were made with an 11-m radio telescope. The CO map considered has a peak near the position of the infrared continuum source. There is little correlation between the CO contours and any optical structure. The CO contours show a pronounced north-south orientation. CS was observed as a representative example of a stable molecule with a higher dipole moment than CO. Questions regarding the structure of Orion A are discussed, giving attention to various models.

Liszt, H. S.↗