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Weinberg, J. L.

Publications and source records attributed to Weinberg, J. L..

At least 37 records · Page 2
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NASA NTRS1976

Skylab experiment SO73: Gegenschein/zodiacal light

A 10 color photoelectric polarimeter was used to measure the surface brightness and polarization associated with zodiacal light, background starlight, and spacecraft corona during each of the Skylab missions. Fixed position and sky scanning observations were obtained during Skylab missions SL-2 and SL-3 at 10 wavelenghts between 4000A and 8200A. Initial results from the fixed-position data are presented on the spacecraft corona and on the polarized brightness of the zodiacal light. Included among the fixed position regions that were observed are the north celestial pole, south ecliptic pole, two regions near the north galactic pole, and 90 deg from the sun in the ecliptic. The polarized brightness of the zodiacal light was found to have the color of the sun at each of these positions. Because previous observations found the total brightness to have the color of the sun from the near ultraviolet out to 2.4 micrometers, the degree of polarization of the zodiacal light is independent of wavelength from 4000A to 8200A.

Weinberg, J. L.↗
NASA NTRS1976

Polarization reversal in the tail of Comet Ikeya-Seki /1965 VIII/

Multicolor observations of brightness and polarization in the continuum throughout the tail of Comet 1965 VIII reveal the presence of positive and negative polarization (polarization reversal) characteristic of slightly absorbing particles. The phase angle of the neutral point is found to vary with color and with time, the latter indicating short-term changes in the properties of the particles after perihelion.

Weinberg, J. L.↗
NASA NTRS1976

Space observations of the zodiacal light

An annotated tabular listing of balloon, rocket, satellite and space probe observations of zodiacal light from 1962 to 1974 is presented. Some selected results concerning zodiacal light observations from Skylab and Pioneers 10 and 11 are discussed, and some remarks on wavelength and spatial coverage of zodiacal light observations are made, noting the paucity of space observations in the ultraviolet and near the sun.

Weinberg, J. L.↗
NASA NTRS1976

Pioneer 10 observations of zodiacal light brightness near the ecliptic - Changes with heliocentric distance

Sky maps made by the Pioneer 10 Imaging Photopolarimeter (IPP) at sun-spacecraft distances from 1 to 3 AU have been analyzed to derive the brightness of the zodiacal light near the ecliptic at elongations greater than 90 degrees. The change in zodiacal light brightness with heliocentric distance is compared with models of the spatial distribution of the dust. Use of background starlight brightnesses derived from IPP measurements beyond the asteroid belt, where the zodiacal light is not detected, and, especially, use of a corrected calibration lead to considerably lower values for zodiacal light than those reported by us previously.

Hanner, M. S.↗
NASA NTRS1976

The S sub 10 /V/ unit of surface brightness

Some discrepancies in the use of the unit of zodiacal light measurements - S sub 10 (V), which is the equivalent number of tenth magnitude stars of solar spectral type per square degree - are discussed. It is suggested that: (1) the S sub 10 (V) unit be understood to represent 10th magnitude solar (G2V) stars per square degree at mean solar distance, (2) the V refers to the visual color in the UBV system defined by Johnson and Morgan (1953), (3) the apparent solar visual magnitude be taken as -26.73 and the B-V index as .63, (4) the solar spectral irradiance values of Labs and Neckel (1970) be used, and (5) when using Vega as a standard to obtain brightnesses in S sub 10 (V), +.04 be used as its magnitude at all wavelengths and the irradiance values of Hayes and Latham (1975) be used.

Sparrow, J. G.↗
NASA NTRS1976

Polarization of the zodiacal light - First results from Skylab

A brief description is given of the Skylab ten color photoelectric photometer and the programs of measurements made during Skylab missions SL-2 and SL-3. Results obtained on the polarized brightness of zodiacal light at five points on the antisolar hemisphere are discussed and compared with other published data for the north celestial pole, south ecliptic pole, at elongation 90 degrees on the ecliptic, and at two places near the north galactic pole.

Sparrow, J. G.↗
NASA NTRS1976

Multicolor photometry of low-light-level phenomena from Skylab

A 10-color photoelectric polarimeter was used during Skylab missions SL-2 and SL-3 to measure sky brightness and polarization associated with zodiacal light, background starlight, and the spacecraft corona. A brief description is given of the instrument and observing routines, together with a listing of observations from Skylab and of coordinated observations from Pioneers 10 and 11 and from the ground. Initial results are presented on the spacecraft corona and on the distribution of brightness and polarization at 7100 A over the antisolar hemisphere.

Weinberg, J. L.↗
NASA NTRS1975

The Skylab ten color photoelectric polarimeter

A 10-color photoelectric polarimeter was used during Skylab missions SL-2 and SL-3 to measure sky brightness and polarization associated with zodiacal light, background starlight, and the spacecraft corona. A description is given of the instrument and observing routines together with initial results on the spacecraft corona and polarization of the zodiacal light.

Weinberg, J. L.↗
NASA NTRS1975

Variations in Gegenschein polarization

Claims made by Bandermann and Wolstencroft (1974) that angular structure and day-to-day variations of the polarized component of the zodiacal light were observed near the antisolar point are shown to be unsubstantiated. The data obtained by Bandermann and Wolstencroft are reviewed together with the instruments they used. It is shown that the incorrect results reported were due to observation errors.

Sparrow, J. G.↗
NASA NTRS1974

Background starlight observed from Pioneer 10

The results of background starlight observations are reviewed that were obtained by the Pioneer 10 asteroid-Jupiter probe when, after passage beyond the asteroid belt, its imaging photopolarimeter observed integrated starlight and diffuse galactic light for the first time in the absence of zodiacal light. Brightnesses in the blue are presented with and without individually resolved stars for regions of the sky observed when Pioneer 10 was 4.64 astronomical units from the sun.

Weinberg, J. L.↗
NASA NTRS1974

Zodiacal light and the asteroid belt - The view from Pioneer 10

Brightnesses measured by the Pioneer 10 imaging photopolarimeter in two regions of sky were compared on sky maps at sun-spacecraft distances from 2.4 to 4.8 AU to determine the spatial extent of the zodiacal light. Data in the ecliptic at elongations greater than 90 deg show negligible contribution to the zodiacal light beyond 3.3 AU, the 2:1 Jupiter resonance. The zodiacal light brightness at 2.4 AU is less than 10% of that observed at 1 AU.

Hanner, M. S.↗
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

Polarization of the zodiacal light

The zodiacal light is described briefly and is compared with other components of the light of the night sky. A chronology is given of observations of the polarization of the zodiacal light, followed by a comparison of results which is used to describe the principal polarization features. Brief mention is made of current satellite experiments to measure the polarization of the zodiacal light.

Weinberg, J. L.↗
NASA NTRS1973

Astronomy through the Skylab scientific airlocks.

Description of Skylab astronomy experiments (other than the Apollo Telescope Mount experiments) designed to study the earth's atmosphere, particles near the spacecraft, various components of the background skylight, the spectra of the sun, and the features of stars, nebulae, and galaxies. Emphasis is placed on the eight experiments that will operate through the scientific airlocks in the Orbital Workshop. The major features of equipment to be used in each experiment are outlined together with characteristics and relevance of information expected in each case.

Henize, K. G.↗
NASA NTRS1973

Observations of zodiacal light from the Pioneer 10 Asteroid-Jupiter probe - Preliminary results.

The imaging photopolarimeter on the Pioneer 10 Asteroid-Jupiter probe is being used to measure starlight and zodiacal light during the cruise phase of the mission. The 2.5-cm-diam telescope is used with a 2.3 deg field of view to spin/scan the sky in the region between 10 and 151 deg from the direction of motion of the spacecraft. Orthogonal components of brightness are measured in two wavelength bands: blue (3900 to 5000 A) and red (5950 to 7200 A). The gegenschein was observed on Mar. 14, 1972, when the earth-sun-spacecraft angle was 3.4 deg and the spacecraft was 9.2 million km from the earth and 1.011 AU from the sun. The distribution of brightness relative to the antisolar point is similar to that obtained from ground-based observations. Taken together, these results show that the gegenschein is not associated with the earth.

Weinberg, J. L.↗