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  • ASTRONOMY
  • 1980-1984  (384)
  • 1970-1974  (93)
  • 1925-1929
  • 1981  (384)
  • 1974  (93)
  • 1929
  • 1
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    Spectroscopy in X-ray astronomy (1981)
    In:  CASI
    Details
    Publication Date: 2006-06-04
    Description: Detailed features in cosmic X-ray sources and their associated temporal variation over a wide energy range were studied. Excess emission and absorption at approximately 6 to 7 kiloelectron volts in the spectra of supernova remnants, binary X-ray sources, and clusters of galaxies were observed. A gas scintillation proportional counter (GSPC) will be used as the detector system. In the gas scintillator the principal limitation is due to the statistics of the initial ionization process only.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 3 p
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  • 2
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    Far ultraviolet astronomy using the FAUST telescope (1981)
    In:  CASI
    Details
    Publication Date: 2006-06-04
    Description: The Far Ultraviolet Space Telescope (FAUST) a compact, wide field-of-view, far ultraviolet instrument designed for astronomical observations of extended and point sources is discussed. The design and application of the instrument are described. The prime objective is to observe faint astronomical sources with sensitivities higher than previously available. Scientific programs will include: (1) a search for ultraviolet stars which are predicted to exist at the stage of evolution prior to the final death of a star; (2) observations of galaxies and quasars; and (3) joint programs with other Spacelab 1 experiments. The secondary objective is to verify the suitability of the Spacelab as a platform for far ultraviolet astronomy: data will be provided on the ultraviolet background levels due to astronomical, terrestrial, and spacecraft generated sources; the levels of contaminants which affect ultraviolet instruments; and the capability of the Orbiter for stable pointing at celestial sources for useful periods of time.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 3 p
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  • 3
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    Thermal instability and energy relations in the convective envelopes of slowly rotating stars (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: The nonstationary convection that arises due to thermal instability in the envelopes of lower Main Sequence stars (and the sun in particular) is investigated. The convection that arises in the envelopes as a result of thermal instability is of nonstationary turbulent nature. It is shown that construction of a consistent model of the zones of turbulent convection in the stars requires the use of the complete heat flux equation with consideration of the terms that appear because of turbulence. Expressions for these additional terms in terms of averaged characteristics of the motion and eddy viscosity coefficients are derived on the basis of the Prandtl-Wasiutinsky theory.
    Keywords: ASTRONOMY
    Type: Interplanet. Medium and Phys. of the Magnetosphere (NASA-TT-F-784); p 203-223
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  • 4
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    The non-existence of the Oort cometary shell (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: The procedures adopted as theory for a shell of comets are shown to be invalid. Any plot of numbers of long-period comets against 1/a will automatically exhibit a peak at small values of this parameter, and cannot be inverted to demonstrate a high volume-density of aphelia in space. The positions of actual aphelion-points show no sign of any concentration at any range. Further, the aphelion-distance undergoes large almost random changes owing to planetary perturbations at each return, and present values can yield no indication of original positions. A recent attempt to save the shell-theory by making use solely of comets with large perihelion-distance is shown to rest on exactly the same errors as have done all the earlier presentations. The plain conclusions emerge that the shell-theory is devoid of any support by facts, and that the alleged shell of comets is non-existent.
    Keywords: ASTRONOMY
    Type: Astrophysics and Space Science; 31; Dec. 197
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  • 5
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    Distance to Cygnus X-1 (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: An evaluation of the nature of the X-ray source Cygnus X-1 depends on distance relations. The validity of distance estimates provided by Margon et al. (1973) and Bregman et al. (1973) is considered. It is concluded that the possibility of a determination of the distance of HDE 226868 to the required accuracy on the basis of reddening measurements appears unlikely. It is, therefore, thought to be premature to suggest that the X-ray source is a black hole.
    Keywords: ASTRONOMY
    Type: Nature; 251; Oct. 18
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  • 6
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    Tail structures far from the head of Comet Kohoutek. I (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Two tail structures 0.1 AU from the head of Comet Kohoutek were photographed during January 1974. One was a wavy structure resembling a helix while the other was an irregular swan-like cloud. Both features were propagating down the tail at approximately 250 km/sec, and the observed speed is probably the phase speed. We discuss the physical origin of these structures and interpret the helix as a kink instability resulting from currents flowing along the tail axis.
    Keywords: ASTRONOMY
    Type: Icarus; 23; Dec. 197
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  • 7
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    Visual observations of Comet Kohoutek from Skylab III (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Sketches of Comet Kohoutek drawn by the author during operations on Skylab are presented. The sketches are black and white, with darker color implying a higher observed brightness. Sketches were also made of what the isophotes would have looked like if they could have been measured. In addition, color sketches made after the flight and corresponding to each of the inflight sketches are presented. The sketches show the comet at perihelion minus 10 days and at perihelion plus 1-9 days. Sketches show the comet changing appreciably in form, color, texture, and length after perihelion. The sunward spike, visible at perihelion plus one day, is no longer visible at perihelion plus 4 days.
    Keywords: ASTRONOMY
    Type: Icarus; 23; Dec. 197
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  • 8
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    Estimations of the smoothing operator response characteristics (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The mean response characteristic of the graphical smoothing method is discussed. The method is illustrated by analysis of latitude observations at Washington from 1915.9 to 1941.0. Spectral density, frequency distribution, and distribution functions are also discussed.
    Keywords: ASTRONOMY
    Type: Astrometrics and Astrophysics, No. 17 (NASA-TT-F-15768); p 145-148
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  • 9
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    The law of distribution of light beam direction fluctuations in telescopes (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The distribution of deviations from mean star trail directions was studied on the basis of 105 star trails. It was found that about 93% of the trails yield a distribution in agreement with the normal law. About 4% of the star trails agree with the Charlier distribution.
    Keywords: ASTRONOMY
    Type: Astrometrics and Astrophysics, No. 17 (NASA-TT-F-15768); p 136-144
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  • 10
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    Scintillation spectra of stars and planets and dependence of their characteristics on meteorological conditions (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Scintillation spectra of stars and planets were obtained at Goloseyevo. The dependence was studied of the scintillation spectral density and of the amplitude and frequency characteristics on zenith distances and aerological parameters. The differences in the scintillation spectra amplitude characteristics for white and red stars were found. The increase in the limiting frequency of the planet scintillation spectrum (as the wind becomes stronger) was studied along with the dependence of spectral characteristics on wind and star azimuth differences.
    Keywords: ASTRONOMY
    Type: Astrometrics and Astrophysics, No. 17 (NASA-TT-F-15768); p 125-135
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  • 11
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    Determination of astronomical refraction near the horizon in different seasons of the year (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The results are presented of astronomical refraction measurements for zenith distances of 80-90 degrees performed in different seasons with a two inch universal instrument. The differences between observed and calculated refraction were found to exhibit seasonal variations, and the results were compared with data of atmospheric aerologic soundings. The great departures in observed refraction from that calculated with the Pulkovo tables were ascribed to temperature gradient changes within the ground kilometer layer of atmosphere.
    Keywords: ASTRONOMY
    Type: Astrometrics and Astrophysics, No. 17 (NASA-TT-F-15768); p 110-124
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  • 12
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    Calculation of the effectiveness of a gamma telescope (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A calculation is given of the effectiveness of recording of gamma quanta by a gamma telescope. Consideration of the isotropic nature of the stream of gamma quanta reaching the gamma telescope revealed that low energy gamma quanta are recorded relatively more effectively, since they are recorded from a wider solid angle than higher energy gamma quanta. The problem is solved of determining the effectiveness of recording of gamma quanta and determination of their energies by a gamma telescope.
    Keywords: ASTRONOMY
    Type: Equipment for Space Res. (NASA-TT-F-785); p 319-334
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  • 13
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    Low noise parametric amplifiers for radio astronomy observations at 18-21 cm wavelength (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The principle characteristics and use of SHF parametric amplifiers for radiometer input devices are explored. Balanced parametric amplifiers (BPA) are considered as the SHF signal amplifiers allowing production of the amplifier circuit without a special filter to achieve decoupling. Formulas to calculate the basic parameters of a BPA are given. A modulator based on coaxial lines is discussed as the input element of the SHF. Results of laboratory tests of the receiver section and long-term stability studies of the SHF sector are presented.
    Keywords: ASTRONOMY
    Type: Equipment for Space Res. (NASA-TT-F-785); p 23-27
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  • 14
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    Comets (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The nature and origin of comets is discussed. Observations of the principal parts of comets, the dust and plasma tails, the hydrogen cloud, the coma and the cometary nucleus, are presented, and the icy conglomerate model of Whipple as extended by Delsemme accounting for the observed properties and their variation with heliocentric distance is examined. The origin of comets is considered in relation to the orbital statistics of the long-period comets and the existence of the Oort cloud on the edge of the solar system, and possible roles for comets in the solar nebula and the evolution of the solar system are indicated. Particular attention is then given to the discovery and properties of Halley's Comet, which is expected to reach perihelion in 1986, and to possible flyby and rendezvous missions to Halley's Comet and others.
    Keywords: ASTRONOMY
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  • 15
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    Electron densities for 10 planetary nebulae derived from the semiforbidden C III lambda 1907/1909 ratio. II (1981)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Electron densities for IC 351, IC 2165, J900, IC 3568, NGC 6644, NGC 6891, IC 4997, NGC 7009, Hu 1-2, and IC 5217 are derived from high-dispersion semiforbidden C III spectrograms. For seven of these nebulae, the derived electron density is larger than the values derived from either surface brightness measurements or forbidden line ratios. Only one object, Hu 1-2, shows pronounced splitting of the semiforbidden C III emission lines due to a large expansion velocity.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 246
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  • 16
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    Medium energy gamma ray astronomy with transpacific balloon flights (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Transpacific balloon flights with the University of California, Riverside (UCR) double scatter telescope are discussed. With flight durations from 5 days up to perhaps 15 days the long observation times necessary for medium energy (1-30 MeV) gamma ray astronomy can be obtained. These flights would be made under the auspices of the Joint U.S.-Japan Balloon Flight Program at NASA. It is proposed that flights can provide at least 30 hours of observation time per flight for many discrete source candidates and 120 hours for detecting low intensity cosmic gamma ray bursts.
    Keywords: ASTRONOMY
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  • 17
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    Studies in astronomical time series analysis. I - Modeling random processes in the time domain (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Several random process models in the time domain are defined and discussed. Attention is given to the moving average model, the autoregressive model, and relationships between and combinations of these models. Consideration is then given to methods for investigating pulse structure, procedures of model construction, computational methods, and numerical experiments. A FORTRAN algorithm of time series analysis has been developed which is relatively stable numerically. Results of test cases are given to study the effect of adding noise and of different distributions for the pulse amplitudes. A preliminary analysis of the light curve of the quasar 3C 272 is considered as an example.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series; 45; Jan. 198
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  • 18
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    Three new 'nonterrestrial' molecules (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Eight new interstellar lines have been detected from three molecules not previously observed spectroscopically in space or in the laboratory. One is a linear or nearly linear molecule with microwave constants B0 equals 21,337.15 plus or minus 0.06 MHz, D0 equals 21.4 plus or minus 1.5 kHz. This is the thioformyl ion HCS(plus), first identified because B0 and D0 are close to those calculated, and now confirmed by laboratory detection of one of the present lines (Gudeman et al.). The second molecule, also linear or nearly so, has microwave constants B0 equals 10,691,406 plus or minus 0.043 MHz, D0 equals 1.84 plus or minus 0.91 kHz close to those expected for the isoelectronic systems HOCO(plus) and HOCN; a choice between the two cannot be made on the basis of the available astronomical data. The existence of a third molecule is deduced from an unidentified line at 85,338 MHz that has been found in many sources, is fairly intense in several, and may be self-absorbed in Sgr B2.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 246
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  • 19
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    Discovery of phase-locked variable polarization in an RS Canum Venaticorum-like star, HR 5110 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Using measurements on 79 nights in 1980 January-August, it is established that the polarization in the ultraviolet (U band) varies synchronously on the known binary period of 2.6132 days, with a peak-to-peak amplitude of 0.03%. The pattern is mainly second harmonic in character, as typical of binary star examples such as Algol and Upsilon Her. Reflection by the cooler star, by a plasma concentration, or both, is suggested. The scale of the polarization seems to be consistent with Rayleigh scattering by neutral hydrogen on the cooler star, and a roughly lambda to the -4th wavelength dependence should be searched for. The QU curve suggests a sizeable inclination for the system, of about 45 deg, but this is preliminary. Separately, a possible weak periodicity might be present on a subsidiary period, conceivably related to a rotating star spot.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 246
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  • 20
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    The 45 micron H2O ice band in the Kleinmann-Low Nebula (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 245
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  • 21
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    Concerning the Wolf-Rayet and other luminous early-type stars (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Effective temperatures, radii, and luminosities were determined from S2/68, ANS, UBV, and uvby photometry for four B0/B1 supergiants, four O4 stars, and four WN7/WN8 stars as well as for four test stars having spectral types between B1.5 V and 09 V and five stars with known angular diameters and effective temperatures. The effective temperatures of B1 Ia+ stars are found to be near 17,000 K, those of O4 stars near 45,000, and those of WN7/WN8 stars near 26,000 K. The question of modeling the atmospheres of hot luminous stars is examined, and it is noted that the photosphere can be modeled adequately using a classical plane-parallel layer model atmosphere. In addition, it is found that the Wolf-Rayet stars of types WN7/WN8 fall in the H-R diagram near the B0 Ia stars, while the others fall near B0.5 III stars. The evolutionary relationship between the Wolf-Rayet and O stars is considered; it is suggested that a Wolf-Rayet spectrum is a short-lived phase in the life of a massive star.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 244
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  • 22
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    Observation of the core of the Perseus cluster with the Einstein solid state spectrometer - Cooling gas and elemental abundances (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Solid State Spectrometer observations of the core of the Perseus cluster have resulted in the detection of X-ray emission lines due to Si, S, and Fe. Analysis of the spectrum indicates that the X-ray emission has at least two characteristic temperatures. This is interpreted in the framework of radiative accretion in the core of the cluster. The derived parameters are a cooling time less than or approximately equal to 2 x 10 to the ninth years for the low-temperature gas, a mass accretion rate of approximately 300 solar masses per year, and a characteristic size of 10-20 kpc for the cool gas. The Fe abundance in the core (approximately 0.4) is similar to the Fe abundance averaged over the whole cluster, indicating that Fe emission is not strongly concentrated about NGC 1275. The Si and S abundances are consistent with solar values.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 244
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  • 23
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    Non-linear stability around the triangular libration points (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The configuration space around the triangular libration points in the Earth-Moon system is partitioned according to the stability of the motion. The regions around L4 and L5 are established where particles placed with zero initial velocity will librate. The complexity of the partitioning is revealed.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics; 23; Mar. 198
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  • 24
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    High-resolution observations of the QSO 3C 345 at 1.3 centimeters (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: High-resolution VLBI observations made at a frequency of 22.235 GHz of the quasar 3C 345 are discussed. Antennas located at the Crimean Astrophysical Observatory, USSR; Onsala, Sweden; Effelsberg, West Germany; and the Haystack Observatory, Massachusetts were employed at 4-min integration times to provide baselines ranging up to 5.5 x 10 to the 8th wavelengths. About 40% of the total flux density of 7.85 Jy, observed in November 1977, and 8.05 Jy, observed in October 1978, is found to originate in an unresolved component of the quasar core in a region less than 0.1 milliarcsec in diameter. The elongated jet-like component of the quasar is observed to contain several peaks of emission extending up to 6 milliarsec from the core which decreased in extent between the two observations.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 243
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  • 25
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    Radio astronomy (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The activities of the Deep Space Network in support of radio astronomy operations during the first quarter of 1981 are reported. Results of the use of a low noise maser are presented, as well as updates in DSN support of experiments sanctioned by the Radio Astronomy Experiment Selection Panel.
    Keywords: ASTRONOMY
    Type: The Telecommun. and Data Acquisition Rept.; p 1-2
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  • 26
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    High-resolution IUE observations of the 1981 eclipse of 32 CYG (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: 32 Cyg shows a spectacular pure emission line spectrum during eclipse. Six weeks later, most lines, which were observed in emission during eclipse, are seen as P Cygni type profiles with strong absorption components. The lines are formed through line scattering of B star light in the extended atmosphere (wind) of the K supergiant. During eclipse, the emission parts of the P Cyg lines remain visible since the size of the line scattering sphere around the B star is larger than the red giant. Other emission lines are formed in a shock front near the B star (CIV, SiIV, FeIII) and possibly in an accretion disk. The strong FeII UV Mult. 191 lambda lambda 1785-88 A is shown to be formed through optical pumping via FeII UV Mult. 9 photons. The phase dependence of the P Cyg type profiles is modelled by means of line transfer calculations in nonspherical, 3-dimensional geometry with velocity fields.
    Keywords: ASTRONOMY
    Type: Smithsonian Astrophysics Observatory 2nd Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, Vol. 1; p 245-259
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  • 27
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    Optical photometry of SS 433 - 200 nights of data 1979-1980 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Results from over 200 nights of optical photoelectric photometry of SS 433 during the period July 1979-October 1980 are presented. The data, taken in unfiltered light, the V band, an interference filter band centered on stationary H-alpha and a far-red band, provide evidence for an underlying 164-day light variation of peak-to-peak amplitudes 0.50 magnitude in V and 0.7 magnitude at 6567 A, and a binary-like variation with period 13.074 days and peak-to-peak amplitudes 0.50 and 0.60 magnitudes, respectively. The 13-day light curves are found to change slightly as a function of phase in the 164-day cycle, while seemingly erratic light fluctuations of up to 1 magnitude in 1 day and about 2 magnitudes in 3-4 days are imposed on both cyclic variations. It is noted that a conventional close-binary model is incapable of accounting for all the observed features, and alternatives involving some sort of luminous, rapidly changing extended low-mass envelope or screen in the binary system must be sought.
    Keywords: ASTRONOMY
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  • 28
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    Infrared photometry of comets Bowell and P/Stephan-Oterma (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Broadband IR photometry in the 1-20 micron range of the comets P/Stephan-Oterma and Bowell shows JHK colors similar to P/Meier and P/Tuttle, which are compatible with the scattering of sunlight by micron-sized grains. In addition, the P/Stephan-Oterma thermal emission was found to have an effective temperature higher than that expected from a blackbody in equilibrium. It is demonstrated that the thermal emission can be fit by models of the dust coma consisting of micron-sized grains, and that most of the flux at all observed wavelengths comes from the dust grains rather than the nucleus.
    Keywords: ASTRONOMY
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  • 29
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    X-ray and VLBI radio observations of the quasars NRAO 140 and NRAO 530 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Einstein X-ray Observatory has confirmed the HEAO 1 detection of the NRAO 140 and NRAO 530 quasars, and found that the low-energy X-ray flux of NRAO 140 is consistent with the high-energy results from the earlier satellite. It is also determined that the X-ray emission from NRAO 530 has either decreased by an order of magnitude, from 1978.0 to 1979.7, or the HEAO 1 field contained a second bright source. The two sources have been observed at 2.8 cm, using a four-station intercontinental VLB array, to find whether the X-ray emission is caused by Compton scattering within the radio components. Dissection of the NRAO 140 into its separate components shows radio parameters that imply a 'Compton problem', in that X-ray emission three orders of magnitude greater than that observed is predicted in one of the components if the source is static. Because the effect is independent of distance, relativistic motion with a Lorentz factor greater than about 40 is required to bring the predicted X-ray flux down to the observed value.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 249
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  • 30
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    Observations of SMC X-1 with the monitor proportional counter on the Einstein /HEAO 2/ X-ray Observatory - The pulse period and its history (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The results of the sixth determination of the pulse period of the X-ray source SMC X-1 are presented. The observations were made in April 1979. The pulse period at this epoch was found to be (0.713683 + or - 0.000032) s referred to phase zero of the binary motion. This result together with all available historical data is utilized to quantify the observed trend toward spin-up. It is found that simple secular trends are not applicable. This finding is interpreted as evidence for additional variations in the pulse period. The obtained results are discussed in the context of present theoretical models for period variations in the binary pulsating X-ray sources. The apparent absence of spin-down episodes in the period history of SMC X-1 is also considered.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 246
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  • 31
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    Two-component X-ray emission from RS Canum Venaticorum binaries (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A summary is presented of results from the Solid State Spectrometer on the Einstein Observatory for seven RS CVn binaries. The spectra of all require two emission components, evidenced by line emission characteristics of plasma at 4-million to 8-million K and bremsstrahlung characteristic of 20-million to 100-million K. The data are interpreted in terms of magnetic coronal loops similar to those seen on the sun, although with different characteristic parameters. The emission regions could be defined by separate magnetic structures. For pressures less than 10 dynes/sq cm the low temperature plasma would be confined within the stellar radii, while the high temperature plasma would, for the synchronous, close binaries, fill the binary orbits. However, for loop pressures exceeding 100 dynes sq cm, the high temperature components would also be confined to within the stellar radii, in loops covering only small fractions of the stellar surfaces. While the radio properties and the occurrence of X-ray flares suggest the larger emission regions, the observations of time variations leave the ambiguity unresolved.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 246
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    Pulsar gamma-rays - Spectra, luminosities, and efficiencies (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The general characteristics of pulsar gamma-ray spectra are presented for a model in which the gamma rays are produced by curvature radiation from energetic particles above the polar cap and attenuated by pair production. It is found that the shape of the spectrum depends on pulsar period, magnetic field strength, and primary particle energy. Comparing numerically calculated spectra with the observed spectra of the Crab and Vela pulsars, it is determined that primary particles must be accelerated to energies of approximately 3 x 10 to the 7th m c-squared. A general formula is determined for pulsar gamma-ray luminosity; it is found to depend on period and field strength.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 245
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  • 33
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    The Uranus occultation of 10 June 1979. I - The rings (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 86; Apr. 198
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  • 34
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    Infrared observations of AE Aquarii (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Broadband infrared observations of the cataclysmic variable AE Aquarii are reported. The observations were obtained in the J, H, K and L filters with the InSb photometer attached to the 1-m telescope of the European Southern Observatory. The infrared energy distribution observed from 0.35 to 3.5 microns for phase 0.5 suggests a spectral type of K5 V for the secondary and a distance to the system of approximately 70 pc if an absolute magnitude of 7.3 is assumed. Monitoring of the flux at 2.2 microns reveals a variability with an amplitude of approximately 0.3 magnitude over one third of the orbital period, the nature of which is under investigation.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 93
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  • 35
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    An X-ray survey of nine historical novae (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Einstein Observatory Imaging Proportional Counter has been used to search for X-ray emission from nine nearby historical novae. Six of the novae have been detected with estimated X-ray intensities between 0.1 and 4 keV of 10 to the -13th to 10 to the -11th erg/sq cm-sec, comparable to the intensities of previously detected cataclysmic variables. The X-ray intensity of one of the novae, V603 Aql, varies over times of several hundred seconds. The data suggest a correlation between the decay rate of the historical outburst and the current X-ray luminosity. Alternatively, the X-ray luminosity may be related to the inclination of the binary system.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 244
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  • 36
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    Pulsar and diffuse contributions to observed galactic gamma radiation (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The first calculation of a gamma-ray production spectrum from pulsars in the Galaxy, along with a statistical analysis of data on 328 known radio pulsars, are presented. The implications of this point source contribution to the general interpretation of the observed galactic gamma-ray spectrum are indicated. The contributions from diffuse interstellar cosmic-ray induced production mechanisms are then re-examined, concluding that pulsars may be contributing significantly to the galactic gamma-ray emission.
    Keywords: ASTRONOMY
    Type: Nature; 290; Mar. 26
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  • 37
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    Variable X-ray spectra of BL Lacertae objects - HEAO 1 observations of PKS 0548 - 322 and 2A 1219 + 305 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 243
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  • 38
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    Phase-correlated P Cygni profile variations of the C III multiplet in UW Canis Majoris (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The interacting close binary system UW CMa has been observed, in the wavelength range from 1161 to 1188 A, continuously during a complete orbital cycle in 1979 with the Copernicus (OAO-3) U2 spectrometer. The C III multiplet at 1175 A, observed as a P Cygni feature, exhbits a clear dependence on the orbital phase of the binary; the radial velocity variation of this feature lags behind that of the O7 primary component by 0.1 orbital phase, which agrees with the anticipations in an earlier study by the same authors. The radiation-driven matter, flowing out of the binary, originates in the primary component.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 94; 2, Fe; Feb. 198
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  • 39
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    VRI photometry of selected SAO stars (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Johnson V, R, and I photoelectric photometry has been obtained for 199 SAO stars in support of the Near Infrared Photographic Sky Survey. These data are utilized in the calibration of survey photographs and are presented here to assist other programs reliant upon access to photometry in the photographic infrared.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 92
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  • 40
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    Deformation of a line-element in the phase space at the triangular libration point (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The flow in the projection of the phase space into the configuration space is presented in the neighborhood of a neutrally (or critically) stable equilibrium point in the restricted problem of three bodies. The projection is a line-element every point of which has zero initial velocity. After the elapse of various times the mapping (the rotations and elongations) of the line-element is described showing chaotic behavior.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics; 23; Feb. 198
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  • 41
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    Stability of outer planetary systems (1981)
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    Publication Date: 2011-08-18
    Description: The conditions for stability in the Liapunov-Hill sense of outer planetary systems are given in terms of radii of planetary orbits. The outer planets of the solar system are found stable and the possible existence of other than the presently known planets between Jupiter and Pluto are indicated. The existence of other planetary systems with arbitrary mass ratios of the primaries is suggested, and the stability conditions for such systems are derived.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics; 23; Jan. 198
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  • 42
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    In quest of telescopes (1981)
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    Publication Date: 2011-08-18
    Description: This article deals with the author's decision to study star formation and reviews the early days of infrared astronomy at O'Brien Observatory. The infrared equipment used to observe the T Tauri variable class is described.
    Keywords: ASTRONOMY
    Type: Sky and Telescope; 61; Feb. 198
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  • 43
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    Radio astronomy (1981)
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    Publication Date: 2011-08-18
    Description: The activities of the Deep Space Network in support of Radio Astronomy Operations during April and May 1981 are reported. Work in progres in support of an experiment selected for use of the DSN by the Radio Astronomy Experiment Selection Panel, Twin Quasi-Stellar Object VLBI, is reported.
    Keywords: ASTRONOMY
    Type: The Telecommun. and Data Acquisition Progr. Rept. 42-64; p 1-9
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  • 44
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    Planetary radar (1981)
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    Publication Date: 2011-08-18
    Description: The radar astronomy activities supported by the Deep Space Network during the first quarter of 1981 are reported. The bodies observed include the asteroids Apollo and Toro, comet Bradfield, and the rings of Saturn.
    Keywords: ASTRONOMY
    Type: The Telecommun. and Data Acquisition Rept.; p 226
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  • 45
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    Radio Astronomy (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The activities of the DSN in support of Radio and Radar Astronomy Operations during September through December 1980 are described. Emphasis is on a report of an experiment selected for use of the DSN by the radio Astronomy Experiment Selection Panel: that of VLBI observations of the energetic galactic object SS-433.
    Keywords: ASTRONOMY
    Type: Telecommun. and Data Acquisition; p 1-2
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  • 46
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    Spectroscopy of the B-gamma line in the Galactic center (1981)
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    Publication Date: 2011-08-18
    Description: Spectra of the B-gamma recombination line of hydrogen in the Galactic center show that the line has central velocities and shapes similar to those reported previously for the Ne II line. Observations are made at 10 positions within the infrared cluster of the Galactic center with a circular diaphragm of diameter 5 arcsec and with a spectral resolution of approximately 85 km/sec. The spectra confirm that the ionized gas in the Galactic center is distributed in discrete clouds.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 86; Apr. 198
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  • 47
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    The 1980 June X-ray high state of Cygnus X-1 - Optical changes (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: UBV photometry of Cygnus X-1 is reported from before, during, and after the 1980 June X-ray high state discovered by the Hakucho satellite. A darkening was recorded around orbital phase 0.25, also near phase 0.0, which persisted for over a month after the X-ray episode. The brightness around phase 0.75 remained normal. Light curves from preceding years are compared. Preliminary mention is also made of polarization changes during the high state.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 244
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  • 48
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    The NASA/Marshall Space Flight Center program in gamma-ray burst astronomy (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The research program in gamma-ray burst astronomy at the NASA/Marshall Space Flight Center is described. Large-area scintillation detector arrays have been flown on high-altitude balloons, and an array is being developed for the Gamma-Ray Observatory. The design of these detectors is described along with results obtained from previous balloon flights.
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  • 49
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    The Goddard program of gamma-ray transient astronomy (1981)
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    Publication Date: 2011-08-18
    Description: The Goddard program of gamma-ray burst studies is briefly reviewed. The past results, present status and future expectations are outlined regarding our endeavors using experiments on balloons. IMP-6 and IMP-7, OGO-3, ISEE-1 and ISEE-3, Helios-2, Solar Maximum Mission, the Einstein Observatory, Solar Polar and the Gamma Ray Observatory, and with the interplanetary gamma-ray burst networks, to which some of these spacecraft sensors contribute. Additional emphasis is given to the recent discovery of a new type of gamma-ray transient, detected on 5 March, 1979.
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  • 50
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    An investigation of the neutral and ionized gas in M16 (1981)
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    Publication Date: 2011-08-18
    Description: An attempt is made to understand the physical and kinematic conditions in the M16 active star formation site, by means of mapping observations of neutral and ionized hydrogen and observations of (C-12)O from selected positions within the H II regions. The 21-cm maps suggest that at least two neutral clouds are present in the M16 complex, one of which is likely to be the remains of the cloud in which star formation initially occurred, and the other is probably the cold gas remaining from a disrupted cloud edge where the ionization front has crossed the cloud-intercloud boundary. Multislit echelle spectra of the H-alpha line are obtained to determine the physical conditions within the ionized gas, and H-alpha maps show that the ionized gas is systematically blueshifted in the east and splits into two streams in the southwest.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 248
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  • 51
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    The Sixth Catalogue of galactic Wolf-Rayet stars, their past and present (1981)
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    Publication Date: 2011-08-18
    Description: This paper presents the Sixth Catalogue of galactic Wolf-Rayet stars (Pop. I), a short history on the five earlier WR catalogues, improved spectral classification, finding charts, a discussion on related objects, and a review of the current status of Wolf-Rayet star research. The appendix presents a bibliography on most of the Wolf-Rayet literature published since 1867.
    Keywords: ASTRONOMY
    Type: Space Science Reviews; 28; 3, 19; 1981
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  • 52
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    Observations of faint Haro galaxies (1981)
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    Publication Date: 2011-08-18
    Description: Spectroscopic and photometric data for 23 faint-compact UV-excess galaxy candidates, found by Haro's three-color technique (1956), are presented. Eighteen were found to be emission-line galaxies (magnitudes between 14.4 and 17.9) with redshifts in the range of 1670 to 39,450 km/s; the remaining five appear to be stars. The apparent compactness of the galaxy images is a result of the finite resolution of the Survey plates. Faint Haro galaxies are not distinguishable from the original Haro galaxies in surface brightness or in their range of color and absolute magnitude. The Haro galaxies correspond to roughly two-thirds of Huchra's non-Seyfert Markarian galaxies (1977 a) which have the most negative (U-B) index; the new Haro galaxies have the same V magnitude growth with aperture, the same (B-V) aperture relation, and the same mean surface brightness as the Markarian galaxies.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 93
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  • 53
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    A solar extreme ultraviolet telescope and spectrograph for Shuttle/Spacelab (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An instrument for advanced studies of the solar corona is described. Its optical system provides nearly stigmatic imaging of selected portions of the sun over the spectral range from 22.5 to 44.0 nm. Both spectroheliograms and emission line profiles of coronal features will be obtained over a wide range of coronal temperatures.
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  • 54
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    The Solar Optical Telescope /SOT/ (1981)
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    Publication Date: 2011-08-18
    Description: The Solar Optical Telescope (SOT) is a 1-m class, high resolution solar telescope which NASA plans to operate on the Shuttle Spacelab during the mid and late 1980's. SOT will provide resolution down to 0.1 arcsec, and can therefore be used to solve many problems of solar atmosphere structure and dynamics. In particular, SOT should provide definite data on (1) the source of the sun's magnetic field, (2) the amount of power in waves generated in the photosphere, (3) the heating of the chromosphere, and (4) the local and global mass and energy balance in the solar transition region. The SOT Scientific Working Group will help plan, develop, and update the overall scientific plan for the SOT, as well as make recommendations with regard to the SOT project, instrumentation optimization, and scientific data management.
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  • 55
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    The planetary nebula NGC 6826 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Monochromatic photographs have established the NGC 6826 nebula as the third member of a group of very rare triple-shell planetaries (Feibelman, 1971, 1974). Kaler (1974) also characterized NGC 6826 as a giant halo planetary. Numerous errors and confusing statements regarding its size, structure and stratification are discussed, and the correct dimensions of the nebula are reported: the inner ring is 12.7 arcsec x 8.7 arcsec (Feibelman, 1971); the outer ring is 27 arcsec x 24 arcsec according to Curtis (1918), 25.7 arcsec x 24.4 arcsec according to Feibelman (1971), and 36 arcsec x 36 arcsec according to Coleman et al. (1975). The halo measurements range in diameter from 110 arcsec (Duncan, 1937) to 130 arcsec (Kaler, 1974) to 142 arcsec (Millikan, 1974). Values for the distance of NGC 6826 range from 0.75-1.16 kpc (Cahn and Kaler, 1971) to 2.265 kpc (Cudworth, 1974).
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 93
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  • 56
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    On the definition of albedo and application to irregular particles (1981)
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    Publication Date: 2011-08-18
    Description: The various definitions of albedo used in planetary astronomy are reviewed. In particular, the Bond albedo, which refers only to the reflected and refracted components, is not applicable to small particles or highly irregular particles, where diffraction is not restricted to a well-defined lobe at small scattering angles. Measured scattering functions for irregular particles are presented in a normalized form and are applied to the case of zodiacal light.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 104; 1, De; Dec. 198
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  • 57
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    Rapid X-ray variability in the Seyfert galaxy NGC 6814 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: In contrast with the Tennant et al (1981) sample of over 30 active galactic nuclei, HEAO 1 A-2 high time resolution X-ray observations of the X-ray emitting Seyfert 1 galaxy NGC 6814 show strong X-ray variability on time scales of less than 3 hr. On a time scale of 90 min, the mean flux varied by a factor of about 2.5, and a characteristic time for variability of 100 + 60 or - 25 sec is obtained by autocorrelation analysis. There is no indication of spectral variability with an upper limit on a change in the power law spectral index of less than about 0.37, for a factor 2 change in intensity. The constraints of such rapid variability on a range of X-ray source mechanisms is discussed.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 251
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  • 58
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    The X-ray structure of Centaurus A (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Einstein X-ray observatory imaging detectors have found X-ray emission associated with several components of the nearby radio galaxy Cen A = NGC 5128: (1) the compact nucleus; (2) an X-ray jet pointed toward the NE radio lobes; (3) the middle NE radio lobe; (4) the disk or dust lane; and (5) diffuse emission extending several arcmin around the nucleus. The intensity of the nucleus changed by a factor of seven over six months. The X-ray jet is considered in terms of thermal, inverse Compton, and synchrotron models. The emission of the NE radio lobe is greater than that expected from inverse Compton or synchrotron processes. Two ridges of emission are found along each edge of the dust lane, within several arcmin of the nucleus. The diffuse X-ray component has a luminosity which is too high to be due to bulge population X-ray sources, but which may be produced by main sequence stars under appropriate circumstances.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 251
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  • 59
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    Spatial observations of the Orion Nebula in the unidentified 3.28 micron feature (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The unidentified infrared emission at a wavelength of 3.28 microns has been mapped in a 5 x 5 arcmin region of the Orion Nebula at a resolution of 30 arcsec along with continuum thermal emission at 3.5 microns in order to gain information on the probable source of the unidentified feature. The 3.28-micron emission is found to be extended over much of the nebula with a distribution very different from that of the 3.5-micron continuum. The ratio of 3.28-micron to 3.5-micron flux density is observed to range from a value of 7 in the Orion ionization ridge to less than 0.15 towards the Becklin-Neugebauer object, and to generally be larger toward the edges of the emitting region than toward the Trapezium. From the observations, it is concluded that the 3.28-micron emission originates in the ionization front between the foreground ionized gas and background molecular cloud, and may be due to thermal emission from complex, less volatile organic substances in grain mantles.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 245
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  • 60
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    Future prospects for gamma-ray astronomy (1981)
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    Publication Date: 2011-08-18
    Description: As gamma-ray astronomy moves from the discovery to the exploratory phase, the promise of gamma-ray astrophysics noted by theorists in the late 1940s and 1950s is beginning to be realized. In the future, satellites should carry instruments that will have over an order of magnitude greater sensitivity than those flown thus far, and, for at least some portions of the gamma-ray energy range, these detectors will also have substantially improved energy and angular resolution. The information to be obtained from these experiments should greatly enhance our knowledge of several astrophysical phenomena including the very energetic and nuclear processes associated with compact objects, astrophysical nucleosynthesis, solar particle acceleration, the chemical composition of the planets and other bodies of the solar system, the structure of our galaxy, the origin and dynamic pressure effects of the cosmic rays, high energy particles and energetic processes in other galaxies especially active ones, and the degree of matter-antimatter symmetry of the universe. The gamma-ray results of the forthcoming programs such as Gamma-I, the Gamma Ray Observatory, the gamma-ray burst network, Solar Polar, and very high energy gamma-ray telescopes on the ground will almost certainly provide justification for more sophisticated telescopes. These advanced instruments might be placed on the Space Platform currently under study by N.A.S.A.
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  • 61
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    The properties of close multiple stars (1981)
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    Publication Date: 2011-08-18
    Description: A reexamination of the properties of close multiple systems is conducted, taking into account recent numerical, analytical, and observational results. The orbital elements of 43 spectroscopic multiple systems are presented in a table. Tables with photometry data of the systems and data describing their properties are also provided. Attention is given to period ratios, mass ratios, orbital coplanarity, stability, lithium abundances and age estimates, and prospects of future observations. Numerical studies indicate that fragmentation produces binary components with mass ratios usually close to 1.0, while fission usually produces mass ratios in the range 0.1-0.5. Using analytical stability criteria, all 27 close multiple systems considered are stable if they are corotating. If they are counter-rotating, four systems are possibly unstable. However, other factors suggest that even these four are probably stable. The solar-type close multiple systems ranged in age from 100 million years to 2,000 million years.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 246
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  • 62
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    HD 202908 - A young, solar-type triple system (1981)
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    Publication Date: 2011-08-18
    Description: HD 202908 is a solar-type, spectroscopic-visual triple system. High-dispersion spectroscopic observations show that the primary visual component is a double-lined spectroscopic binary with a period of 3.966 days and a mass ratio of 1.0. Velocity changes due to motion in the long-period, 76-year orbit are now perceptible. Over the next 5 years, these changes may amount to 30 km/s for the single star. Continued spectroscopic and visual observations through nodal and periastron passage of the highly eccentric visual orbit, which will occur nearly simultaneously about 1985.5, will permit the accurate determination of the masses and luminosities of the three components. Contrary to expectation, the short-period and long-period orbits are not coplanar. The large lithium abundances, strength of the Ca II emission lines, and rotational velocities all suggest that this multiple system has an age similar to that of the Hyades cluster.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 248
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  • 63
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    Infrared charge-injection-device array performance at low background (1981)
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    Publication Date: 2011-08-18
    Description: Low-background tests of a 1 x 32 Si:Bi charge-injection-device (CID) IR detector are carried out to evaluate its feasibility for space-based astronomical observations. Optimum performance is obtained at a temperature of 11 K. The sensitivity is found to compare well with that of discrete extrinsic silicon photoconductors. The measured sensitivity and the apparent absence of anomalous effects make extrinsic silicon CID arrays very promising for astronomical applications.
    Keywords: ASTRONOMY
    Type: Applied Optics; 20; Sept. 15
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  • 64
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    Meter-wavelength VLBI. I - Cassiopeia A (1974)
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    Details
    Publication Date: 2011-08-16
    Description: Very-long-baseline interferometric observations of the supernova remnant Cassiopeia A, at 74 MHz with a 12,000-wavelength baseline and at 111 MHz with a 18,500-wavelength baseline, are reported. The fringe amplitudes are strongly varying on a time scale of about 15 to 30 minutes, which is attributed to much the same complex structure as that observed at higher frequencies, plus one other compact source. Due to the poor (u, nu)-plane coverage, the location of the extra source can not be isolated unambiguously, but possibilities are suggested. The source must lie outside the supernova remnant shell, possibly associated with a concentration of emission north of the shell, or lying outside the gap in the northeastern side of the shell. The flux and spectral index deduced for the compact source depend on the assumed size, with a range of 100 Jy and 500 Jy at 74 MHz. If the source is associated with the supernova explosion, it must have been traveling at least 5000 km/sec.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 79; Nov. 197
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  • 65
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    Optical monitoring of 15 quasars (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The data of fifteen quasars are analyzed to determine how well a short-term program of observation can characterize the general optical behavior as compared to a long-term program. Three major research objectives were pursued, namely, to measure archival brightness of the quasars, to compare the brightness observed (mid-1970) to that of the Harvard historical plate collection 1900-1950, and to compare the general behavior during a short-time (two years) to that found over 50 years. Results show that in eight of the 15 quasars the mean magnitude derived from the present short-epoch program differed by 0.11 mag or less from the mean determined in the long-epoch program. The mean difference for all 15 quasars was 0.20 mag. However, in two cases, the short program failed by 0.83 and 0.66 mag, respectively, in predicting the mean brightness. The largest rate of increase in brightness observed was 0.9 mag/day (3C263) and of decrease was 0.44 (3C345), and it is concluded that the rates of decrease and increase in brightness are essentially the same.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 86; May 1981
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    Determination of the potential in a synodic system (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Determination of the potential field in a fixed (inertial) system may be accomplished by the solution of a homogeneous linear partial differential equation when a family of orbits of a body moving in the field is given. This partial differential equation was presented and thoroughly analyzed earlier. The present paper discusses the same problem in a rotating system where the centrifugal and Coriolis effects render the pertinent partial differential equation in general non-homogeneous and non-linear. A linear, though non-homogeneous, partial differential equation for the determination of the synodic potential is obtained only in the special case of iso-energetic families of orbits.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics; 24; May 1981
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  • 67
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    Measurements of forbidden line radiation of Ar II /6.99 microns/ in W3 IRS 1 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 244
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  • 68
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    Morphological study of the time histories of gamma-ray bursts (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Time histories of gamma-ray bursts have revealed a great diversity, both in total duration and in the details of fine time structure. Results of the gamma-ray experiment on the Helios-2 spacecraft have suggested some similarities in time profiles of events. The possibility of some characteristic 'separation times' in events may also be indicated.
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  • 69
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    High-speed photometry of the 11 December 1979 Juno occultation (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The occultation of SAO 115946 by Juno on 11 December 1979 was observed from two sites in southern California with portable two-color, high-speed photometers. A composite light curve was constructed from the data by suitable scaling of individual observations, using an astrometric solution for the location of the contact points on Juno's limb. The preliminary astrometric solution used here has a semiminor axis of 118 km and a semimajor axis of 145 km at position angle 75.5 deg. The composite light curve is compatible with a stellar radius of (1.6 + or - 0.8) x 10 to the -4th arcsec, consistent with the radius estimated from the color and visual magnitude. There is no evidence for any companions to SAO 115946 or Juno. The prospects for use of asteroid occultations to determine stellar radii and asteroid surface slopes are discussed as compared with the lunar occultation technique.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 86; Jan. 198
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  • 70
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    A 5.57 hour modulation of the X-ray flux from 4U 1822-37 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The X-ray flux of 4U 1822-37 is shown to be modulated with the 5.57 hr period of its optical counterpart. The X-ray light curve is two component, with a smooth sinusoidal-like 25% semiamplitude modulation and a 30 minute dip of approximately 0.2 in phase following the other minimum; the dip center occurs 0.04 in phase after the optical minimum. The X-ray spectrum is a relatively flat power law up to 17 keV, above which it steepens; iron emission is detected at 6.7 keV with a 4 keV FWHM and an equivalent width of 1100 eV. An excess below 2 keV is consistent with either a 0.25 keV thermal component of 350 eV equivalent width iron L emission. Modeling the eclipse for a 0.5-0.7 solar radius companion gives a system inclination of 70-79 deg and a spherical cloud radius of 0.2-0.3 solar radius. Models for the long-term modulation are considered, and a comparison of the properties of 4U 1822-37 with those of Cyg X-3 shows that they are similar systems.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 247
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  • 71
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    Extremely red compact radio sources - The empty field objects (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Radiation of 10 microns has been detected from 1413+135, one of the very red objects discovered by Rieke, Lebofsky, and Kinman (1979) at near-infrared wavelengths. The spectrum of this object flattens at wavelengths longer than 2.2 microns. Upper limits are also given for the 10-micron emission from 2255+14, 0026+34, and 0406+121. Photometry between 1.25 and 2.2 microns confirms the variability of 1413+135, 2255+41, and 0406+121. Five percent resolution spectra of 1413+135 and 0406+121 between 1.5 and 2.4 microns show no emission or absorption lines. The spectral data rule out the possibility that 1413+135 is a quasar with normal line strengths and a redshift less than 1.3 and greater than 4. The lack of features of the 1.5-2.4-micron spectra, the rapid variability, and the overall shape of the radio, infrared, and X-ray energy distributions are consistent with a BL Lac nature for these objects.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 247
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  • 72
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    Are we beginning to understand T Tauri stars (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An international meeting of astronomers in April 1981 in Portugal to discuss recent data on T Tauri stars is described. It is pointed out that T Tauri stars all vary irregularly in brightness, occur in intimate association with dusty molecular clouds, and exhibit bright optical emission lines, principally of hydrogen, helium, and iron. Stars with masses roughly 0.2 to three times the sun's and with ages from 100,000 to 1,000,000 years are typical of the T Tauri regime. It is thought that the often rich emission-line spectra seen at visible wavelengths indicate the presence of a stellar chromosphere, where the temperature rises steeply from the usual cool photospheric values around 4,000 to 5,000 K. Even though a recent extensive survey of T Tauri stars has been completed, no clear role for rotation in producing radio emission or stellar winds has yet emerged.
    Keywords: ASTRONOMY
    Type: Sky and Telescope; 62; Oct. 198
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  • 73
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    The Space Telescope (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Space Telescope, still under construction, is discussed in light of the constraints imposed on ground-based telescopes. The history of the Space Telescope is traced from its conceptual origin to its actual construction, and design considerations used to determine the Space Telescope construction are described. The optical system of the telescope will have an aperture of 2.4 m, a focal ratio of 24, and a front of primary to focus of 1.5 m. The fine guidance system will use astigmatic images at the edge of the field of view to provide the guidance signal for maintaining stability to 0.007 arcseconds. The guidestars are required for 85% of random fields located at the galactic poles, and the system sensitivity must meet performance specifications for stars brighter than 13.5 magnitude. The scientific instruments - the wide field camera, the faint object camera, the faint object spectrograph, the high resolution spectrograph, the high speed photometer, and the fine guidance sensors - are discussed in detail. Finally, the operations system, including schedule contraints and the Science Institute, is presented.
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  • 74
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    The large- and small-scale structures of 3C 293 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A Very Large Array (VLA) 1.465-GHz map of the radio galaxy 3C 293 shows that the source, which is unusual in that it is dominated by a steep-spectrum extended core, has a two-sided Z-shaped structure whose physical association with the galaxy VV 5-33-12 is now clear. The core is resolved by the Multi-Element Radio Linked Interferometer Network (MERLIN) at 1.666-GHz, and the VLA at 15.035 GHz, into an inner, two-sided structure within 1 kpc of the center of VV 5-33-12, and curved bridges of emission linking this structure to the large-scale emission. The major axis of the core lies 35 deg from the major axes of the emission bridges that make up the bar of the large-scale Z structure, and 60 deg from the minor axis of VV 5-33-12. Precessional and buoyant-refraction models for these misalignments are discussed.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 86; Sept
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  • 75
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    Summary of the workshop on active galaxies and quasars (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The paper reports highlights of discussions carried out at the Tenth Texas Symposium on Relativistic Astrophysics concerning BL Lacertae objects and quasars and their relationship to active galactic nuclei. The discussions considered X-ray, optical and radio observations of active galaxies and quasars showing features which may be interpreted as jets or beams, and X-ray and VLBI observations of core-jet structures exhibiting apparent supraluminal expansion. Attention was also given to the properties of the energy source in the center of the active galaxies and quasars, the nature of quasar emission line regions, the production of the continuum in quasars and active galactic nuclei, and evidence for the association of quasars and BL Lac objects with galaxies.
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  • 76
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    Five-color band ultraviolet photometry of fourteen close binaries (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Photometric observations obtained with the Astronomical Netherlands Satellite in five ultraviolet wavelength regions for 14 close binaries are presented. Strong excess far-ultraviolet flux is detected in four objects. The binaries TT Hya, RX Cas, and SX Cas exhibit a pronounced excess of far-ultraviolet flux, which is thought to be the result of mass transfer phenomena in these systems. Observations of the binary R Ara show very peculair variations; its far ultraviolet flux at 1550 A brightened by 0.4 mag between phases 0.7 and 0.8, while its near ultraviolet flux at 3300 A decreased by 0.5 mag over this same half-day interval. The A0 II-III component in the system RZ Sct is seen to dominate the ultraviolet spectrum.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series; 47; Dec. 198
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  • 77
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    Image tube spectroscopic studies of rapid variables. IV - Spectroscopic and photometric observations of AE Aquarii (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Photoelectric and time-resolved spectroscopic observations of the short-period eruptive binary AE Aqr are presented. The system has a period of 0.4116537 days, and emission and absorption-line components equal to 135 km/sec and 159 km/sec, respectively. The spectral type of the absorption-line component is found to be K5V, from which M1 = 0.82 solar mass, M2 = 0.69 solar mass, and i = 64 deg. A predominantly Ca II emission region occurs on the hemisphere of the K5V star facing the broad emission-line component, whose center of light is located 0.64 of the way from the inner Lagrangian point to the center of mass of the K star. This emission appears to be associated with the transfer of mass from the K5V star to the accretion disk surrounding the primary. In the absence of flare activity, the light of the system is variable in the orbital period with a range in V of about 0.16 mag; maxima occurs near the times of maximum recession velocity and during the approach of each of the two components of the system (0.25 P and 0.80 P).
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 104; 1, De; Dec. 198
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  • 78
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    CTB80 - A galactic radio source with directed jets (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Recent investigations of the galactic radio source CTB 80 reveal several jet-like structures which can be traced outward to over 30 pc from a point less than 0.1 pc within a central core. If the object is associated with a supernova of 1408, then the jets must move out at a velocity of 0.2 C and can only be about 572 years old. The morphology of the whole source, however, suggests a significant, proper east to west motion of the central object, and indicates a much older age. In this case, continuous ejection into the jets would have occurred for tens of thousands of years. A quantitative explanation is presented in which the supernova explosion ejects several massive path-cutting fragments. It thus appears that the extended jets in CTB 80 do emanate from a small core which is energized by a compact object, but the source of this continuous ejection process still remains unknown
    Keywords: ASTRONOMY
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  • 79
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    X-ray and optical observations of the November 19, 1978 gamma-ray burst source region (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Nov. 19, 1978 gamma-ray burst (GRB) has a very well determined error box, 10 square arcmin (Cline et al., 1981). An 8000-sec IPC exposure with the Einstein Observatory detected, at a 3.4-sigma level, one low intensity (less than 3 x 10 to the -13th erg/sq cm per sec) X-ray source inside the error box. The probability of a serendipitous detection was 0.01. Inside the X-ray source error box there are two weak radio sources, one of them highly polarized (Hjellming and Ewald, 1981), and two 20-magnitude objects, not coincident with the radio sources visible in the ESO/SRC J and R plates. With the exception of N49, this is the first possible detection of X-ray emission inside a GRB box. Its low intensity justifies, in fact, the lack of detection for other events.
    Keywords: ASTRONOMY
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  • 80
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    OH emission in the direction of TV Gem and BI Cyg (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The NRAO-Green Bank 43-m telescope and 18-cm receiver have detected OH maser main-line emission at 1665 MHz, in the direction of the two late-type supergiants TV Gem and BI Cyg. The detection of the two new OH maser sources is noteworthy in view of the small number of late-type supergiants known to be molecular radio sources, or associated in close proximity with OH emission clouds. The IR, UV and radio properties of the two stars are discussed.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 86; Dec. 198
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  • 81
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    Preliminary orbital parallax catalog (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The study is undertaken to calibrate the more reliable parallaxes derived from a comparison of visual and spectroscopic orbits and to encourage observational studies of other promising binaries. The methodological techniques used in computing orbital parallaxes are analyzed. Tables summarizing orbital data and derived system properties are then given. Also given is a series of detailed discussions of the 71 individual systems included in the tables. Data are listed for 57 other systems which are considered promising candidates for eventual orbital parallax determination.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series; 47; Nov. 198
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  • 82
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    The 805 second X-ray pulsar H2252-035 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It is shown that the X-ray flux from the 3.6 hr binary system H2252-035 is modulated at a period of 805 sec, and that its spectrum is consistent with either (1) a 1.4 photon index power law, or (2) a greater-than-20-keV thermal model. A 560 + or - 350 eV equivalent-width iron line at about 6.7 keV is noted, and the possibility that the H2252-035 system contains a slowly rotating neutron star is discussed.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 249
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  • 83
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    The stellar contribution to the galactic soft X-ray background (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Log N-log S relations for stars are constructed based on median X-ray luminosities for dF, dG, and dK stars previously reported for the Einstein Observatory/Center for Astrophysics stellar survey and on a detailed X-ray luminosity function derived here for dM stars, and the stellar contribution to the diffuse soft X-ray background is investigated. The principal results are that stars provide approximately 20% of the soft X-ray background in the 0.28-1.0 keV passband and therefore contribute significantly to the soft X-ray background in this energy range (with dM stars constituting the dominant contributing class), and that the stellar contribution to the diffuse X-ray background in the 0.15-0.28 keV passband is less than approximately 3%.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 249
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  • 84
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    Microwave interferometry of Saturn: Application to the brightness temperature of the rings (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Radio interferometric measurements of Saturn and Saturn's rings are explained. The measurements are limited to Mu is greater than or equal to 3. Data are also given on visibility functions, flux density, and brightness temperature.
    Keywords: ASTRONOMY
    Type: NASA, Washington The Rings of Saturn; p 97-105
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  • 85
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    Short wavelength radio observations of Saturn's rings (1974)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Passive radio observations are discussed from 1 mm to 2 cm wavelengths. The interferometric technique was used to observe the brightness of the rings. The reflectivity and disk temperature are also considered. The differences between radio and radar observations are examined and discussed.
    Keywords: ASTRONOMY
    Type: NASA, Washington The Rings of Saturn; p 83-96
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  • 86
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    Balloon infrared astronomy platform (BIRAP) (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The development of a balloon-borne attitude control system for infrared astronomy studies is discussed. The Balloon Infrared Astronomy Platform (BIRAP) is the result of the development effort. The BIRAP uses electronic gimballing for the offset pointing which eliminates a set of mechanical gimbals. Guide stars with visual magnitudes as low as plus 6 are used for fine tracking assuring that all areas of the sky can be covered. The BIRAP control concept uses a closed loop system in the airborne equipment with automatic update through a command link that can be operated either manually or automatically by a ground based computer.
    Keywords: ASTRONOMY
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 268-283
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  • 87
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    AIROscope stellar acquisition (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The acquisition system which operates in conjunction with a balloon-borne TV system, boresighted to a telescope is described. It has two main functions, a star field monitor and an offset star tracker. The design of the system was strongly influenced by the TV camera, which uses the same interlaced scanning system as is employed in commercial television broadcasting. To reduce power and bandwidth requirements, the star field information transmitted in our system consists only of the horizontal and vertical coordinates of each star and its brightness. As a star field monitor the system provides video thresholding, camera blemish suppression, coordinate digitization in 3 axes, circuity to recognize as single star the dispersed video signals resulting from one star overlapping adjacent scanning lines and storage of all signals for readout by the telemetry at appropriate times.
    Keywords: ASTRONOMY
    Type: Telescope Systems for Balloon-Borne Res.; p 225-238
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  • 88
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    A high sensitivity balloon-borne X-ray telescope system (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A high sensitivity X-ray telescope system suitable for photometric type observations from balloon altitudes is described. The balloon gondola system is defined to include the performance requirements and the overall performance requirements of the balloon gondola support system. Diagrams of the gondola and the installed components are provided. The pointing and control system of the telescope is analyzed.
    Keywords: ASTRONOMY
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 176-189
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  • 89
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    The stellar and solar tracking system of the Geneva Observatory gondola (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Sun and star trackers have been added to the latest version of the Geneva Observatory gondola. They perform an image motion compensation with an accuracy of plus or minus 1 minute of arc. The structure is held in the vertical position by gravity; the azimuth is controlled by a torque motor in the suspension bearing using solar or geomagnetic references. The image motion compensation is performed by a flat mirror, located in front of the telescope, controlled by pitch and yaw servo-loops. Offset pointing is possible within the solar disc and in a 3 degree by 3 degree stellar field. A T.V. camera facilitates the star identification and acquisition.
    Keywords: ASTRONOMY
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 167-175
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  • 90
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    Low-background air-infrared telescope for balloon-borne infrared astronomy (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The design and performance of a far-infrared telescope are discussed. The instrument is twenty centimeters in diameter and has excellent operating characteristics at 100 microns. The principal features of the telescope are summarized. A diagram of the system is provided. The telescope completed two sucessful balloon flights in which the planets Mars and Saturn were used as calibration sources. Observations were made of the H2 regions W 3, Orion A, NGC 2024, and the bright infrared galaxy M 82.
    Keywords: ASTRONOMY
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 145-149
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  • 91
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    AIROscope: Ames infrared balloon-borne telescope (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A balloon-borne telescope system designed for astronomical observations at infrared wavelengths is discussed. The telescope is gyro-stabilized with updated pointing information derived from television, star tracker, or ground commands. The television system furnishes both course and fine acquisition after initial orientation using a pair of fluxgate servo compasses. Command and control is by a UHF link with 256 commands available. Scientific and engineering data are telemetered to the ground station via narrow band F.M. in the L band. The ground station displays all scientific, engineering and status information during the flights and records the command and telemetry digital bit stream for detailed analysis. The AIROscope telescope has a 28-inch diameter primary mirror and Dall-Kirkham optics. The beam is modulated by oscillating a secondary mirror at 11 or 25 Hz with provision for left or right beam fixed positions by command.
    Keywords: ASTRONOMY
    Type: Telescope Systems for Balloon-Borne Res.; p 120-135
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  • 92
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    A cooled telescope for infrared balloon astronomy (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The characteristics of a 16 inch liquid helium cooled Cassegrain telescope with vibrating secondary mirror are discussed. The telescope is used in making far infrared astronomical observations. The system houses several different detectors for multicolor photometry. The cooled telescope has a ten to one increase in signal-to-noise ratio over a similar warm version and is installed in a high altitude balloon gondola to obtain data on the H2 region of the galaxy.
    Keywords: ASTRONOMY
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 81-90
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  • 93
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    Design and performance of a 39cm balloon-borne telescope (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A system for stabilizing a balloon-borne telescope using a star sensor device is described. Guide stars from minus four to plus four magnitude can be used and the sensor may be offset with respect to the telescope by as much as plus or minus five degrees in elevation and cross elevation to enable parts of the sky containing no suitable guide stars to be viewed. Acquisition of the guide star and setting of the offset coordinates is carried out by ground command and both may be changed in flight. The main design parameters of the equipment are summarized. Block diagrams and circuit diagrams of the star tracker are provided.
    Keywords: ASTRONOMY
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 58-70
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  • 94
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    Astronomical observations with the University College London balloon borne telescope (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The characteristics of a telescope system which was developed for high altitude balloon astronomy are discussed. A drawing of the optical system of the telescope is provided. A sample of the signals recorded during one of the flights is included. The correlation between the infrared flux and the radio continuum flux is analyzed. A far infrared map of the radio and infrared peaks of selected stars is developed. The spectrum of the planet Saturn is plotted to show intensity as compared with wavenumber.
    Keywords: ASTRONOMY
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 17-25
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  • 95
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    Spectrophotometry of faint comets: The asteroid approach (1981)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Observing programs at optical (0.35-0.8 micron) and near-infrared (1.1-2.4 micron) wavelengths, directed at the acquisition of reflection spectra of faint and distant comets, are described. The ultimate goal is to obtain spectrophotometric measurements of comets for which a significant part of the light is expected to be reflected by the solid surface of the nucleus.
    Keywords: ASTRONOMY
    Type: Mod. Observational Tech. for Comets; p 63-69
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  • 96
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    Outburst and nuclear breakup of Comet Halley - 1910 (1981)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Computer processing of five plates of Comet Halley taken during the 1910 apparition shows that on May 24 strong asymmetric (with respect to the tail axis) fountain-like parabolic plumes had developed on the sunward side of the nucleus. Visual observations showed that after an initial fading while passing in front of the sun, the brightness increased to about magnitude 1. On the plates taken May 31, the nucleus is clearly divided into at least three parts of nearly equal brightness. However, the last plate on June 3 shows a symmetrical coma with a small stellar-like nucleus.
    Keywords: ASTRONOMY
    Type: JPL Mod. Observational Tech. for Comets; p 216-219
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  • 97
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    Existing cometary data and future needs (1981)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: To assist scientists studying comets and their interaction with the interplanetary medium, compilations of existing cometary observations and data plans for additional publication are reported. The works cited include updates and/or supplements to: (1) the Catalogue of Cometary Orbits, (2) Physical Characteristics of Comets, (3) the Atlas of Representative Cometary Spectra, (4) the Atlas Cometas-Viento Solar, (5) the Isophotometrischer Atlas der Kometen, and (6) the Atlas of Cometary Forms. An Atlas of Cometary Spectra and an Atlas of Comet Halley 1910 (II) photographs and spectra are in preparation.
    Keywords: ASTRONOMY
    Type: JPL Mod. Observational Tech. for Comets; p 213-215
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  • 98
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    The ESA mission to Comet Halley (1981)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The Europeon Space Agency's approximately Giotto mission plans for a launch in July 1985 with a Halley encounter in mid-March 1986 4 weeks after the comet's perihelion passage. Giotto carries 10 scientific experiments, a camera, neutral, ion and dust mass spectrometers, a dust impact detector system, various plasma analyzers, a magnetometer and an optical probe. The instruments are described, the principles on which they are based are described, and the experiment key performance data are summarized. The launch constraints the helicentric transfer trajectory, and the encounter scenario are analyzed. The Giotto spacecraft major design criteria, spacecraft subsystem and the ground system are described. The problem of hypervelocity dust particle impacts in the innermost part of the coma, the problem of spacecraft survival, and the adverse effects of impact-generated plasma aroung the spacecraft are considered.
    Keywords: ASTRONOMY
    Type: JPL Mod. Observational Tech. for Comets; p 284-312
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  • 99
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    Laboratory Research (1981)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: To properly interpret the rapidly growing body of data from comet observations, many types of laboratory measurements are needed. These include: (1) molecular spectroscopy in the visible, ultraviolet, infrared and microwave region of the spectra; (2) laser fluorescent spectroscopy of photofragments; (3) laboratory cross-section or reaction rate measurements using flow tube techniques, fluorescent spectroscopy detection for neutrals and ion-molecule reaction techniques; (4) experiments to simulate solar-wind interactions with comets; (5) studies of the properties and behavior of ice mixtures; (6) experiments on the sublimation rate of ice, and the phase transition from amorphous to crystalline ice; (7) investigations of the irradiation of ice; and (8) the electron impact dissociation and excitation of molecules of cometary interest. A nearly completed experiment on the proton irradiation of ice is described.
    Keywords: ASTRONOMY
    Type: JPL Mod. Observational Tech. for Comets; p 251-256
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  • 100
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    Astronomical data bases and retrieval systems (1981)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The status of the development of machine-readable stellar and extragalactic data bases is summarized, including several examples of astronomical applications using these data sets. The creation of a computerized bibliographical data base for cometary research is described.
    Keywords: ASTRONOMY
    Type: JPL Mod. Observational Tech. for Comets; p 232-236
    Format: application/pdf
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