bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation of the amount of hydrogen along the galactic ridge
Authors: Schmidt-Kaler Th.
Published: July 2016

The integralNHof neutral-hydrogen density along the line of sight is determined from the Kootwijk and Sydney surveys. The run ofNHwith galactic longitude agrees well with that of thermal continuous radiation and that of the optical surface brightness of the Milky Way.
Observations of the 158 α recombination line
Authors: Dieter Nannielou H.
Published: July 2016

At Hat Creek I have observed the 158 α line at 1651 MHz in seventeen H 11 regions, some in common with Mezger and Höglund (1967) and some additional ones. The Cygnus-X region in particular has, in this preliminary survey, yielded four sources of the 158 α line. A further survey of about forty H 11 regions will be undertaken soon.
The non-thermal radio-emission from the Galaxy
Authors: Baldwin J. E.
Published: July 2016

In this review of the non-thermal continuum radiation from the Galaxy, the following issues are discussed:

(1)

The non-thermal continuum radiation in the disk.

(2)

Evidence for spiral arms in the non-thermal continuum, and the origin of the radiation in sources or in large-scale magnetic fields.

(3)

The nature of the spurs extending to high galactic latitudes.

(4)

Evidence for the existence or absence of a radio halo.

(5)

The galactic radio spectrum and its relation to the cosmic-ray electron spectrum.

(6)

Supernova remnants, their structure and spectra.

(7)

A comparison of the Galaxy with other normal galaxies.

(8)

Observational needs.
Haloes of galaxies
Authors: Mills B. Y.
Published: July 2016

Observations of 25 galaxies with a 1.5 fan beam at 408 MHz allow coronas of about the size of the optical object; no large haloes have been found.
Spectral data for galactic X-ray sources and their implications for gamma-ray observations
Authors: Tanaka Y.
Published: July 2016

The available information on the spectra of Sco X-1, Tau XR-1, Cyg XR-1 and of the background X-ray emission is summarized. Sco X-1 has an exponential spectrum; the other spectra can be represented by simple power laws. Possible mechanisms for the X-ray emission of the sources are briefly discussed.

Comparison of gamma-ray observations with extrapolations of X-ray spectra suggests that gamma-ray emitters may be found among X-ray sources. The importance of gamma-ray observations to studies of interstellar matter is stressed.
Observations of interstellar extinction in the ultraviolet with the OAO satellite
Authors: Bless R. C. , Savage B. D.
Published: July 2016

We present a preliminary analysis of a number of spectrophotometric scans of reddened and unreddened early-type stars obtained with the OAO-A2 satellite. The principal findings are: (1) all the extinction curves show a ‘bump’ at 1/λ ≈ 4.5; (2) most extinction curves show a minimum at 1/λ ≈ 5.5–6.0; (3) all the extinction curves show a rapid rise in the far ultraviolet; and (4) there appear to be real differences in the far ultraviolet extinction. A brief comparison of our observed extinction curves is made with theoretical particle models.
On dielectric models of interstellar grains
Authors: Greenberg J. Mayo , Stoeckly R.
Published: July 2016

Silicate, ice, and silicate core-ice mantle particles are considered with a view to describing or predicting ultraviolet features in both extinction and polarization which depend on the dielectric nature of the particles.
The interstellar extinction curve from 4000 Å to 6500 Å
Authors: Walker G. A. H. , Hutchings J. B. , Younger P. F.
Published: July 2016

Interstellar extinction curves (mext vs. 1/λ) of 20 Å resolution have been obtained at the DAO from photoelectric scanner observations in the range 4000 Å to 5000 Å for five stars, and of 50 Å resolution for four stars in the range 4000 Å to 6500 Å from Willstrop's photoelectric data. There is a closely linear section between 4900 Å and 5800 Å for all of the curves. There are changes of gradient or discontinuities associated with the broadest diffuse interstellar bands at 6180 Å, 4882 Å, 4761 Å and 4430 Å. There is a marked discontinuity near 5800 Å and for some stars a broad absorption near 4200 Å. The 4430 Å band lies between two unequal wings of anomalously low extinction (one of which has been detected at Edinburgh). The irregularities vary from star to star, and those in the neighbourhood of the 4430 Å band seem to have the same form as those in the region of the absorption peak at 2200 Å
Far-ultraviolet intensities of Orion stars
Authors: Carruthers George R.
Published: July 2016

Photometric data in the 1050–1180 Å and 1230–1350 Å wavelength ranges, and electronographic spectra in the 1000–1600 Å wavelength range, were obtained in an Aerobee rocket flight on January 30, 1969. The spectral intensities derived from these data for main-sequence stars are in good agreement with the model atmospheres of Morton and co-workers. Giant and supergiant stars, however, appear to be up to one magnitude weaker, at 1115 Å, than main-sequence stars of the same spectral class.

The correction for interstellar reddening appears to be not inconsistent with a 1/λ extrapolation of earlier determinations of Smith (1967) and Stecher (1965), except in the case of θ Ori, in which the predicted color excess appears to be much too great, confirming the existence of a peculiar reddening law in the Orion Nebula region.
Absolute stellar photometry in the region 1200 Å–3000 Å
Authors: Campbell J.W.
Published: July 2016

Since 1962 the Space Research Division of the Royal Observatory Edinburgh have been planning and launching a number of rocket experiments aimed at observing the absolute stellar fluxes of early-type stars in the region 1000 Å–3000 Å. Although some earlier attempts were unsuccessful due to rocket failures, good photometric data have been obtained from four successful flights in 1967 and 1968, and it is the purpose of this short report to indicate the nature of the data rather than give a complete scientific analysis.
Observations of Strong Stellar Lines with the OAO
Authors: Code A.D. , Bless R. C.
Published: July 2016

This paper reports on preliminary analysis of spectral scans of early-type stars obtained with the Orbiting Astronomical Observatory. The discussion is confined to the spectra of 50 stars observed with a resolution of approximately 10 Å over the spectral interval from 1050 Å to 2000 Å. Following a qualitative description of the spectra, observed equivalent widths of the Siiv (1400 Å) and Civ (1550 Å) lines are compared with model atmosphere calculations. The results suggest an upward revision of the stellar temperature scale for stars earlier than B3 V.
A discussion of the theory for interpreting ultraviolet stellar spectra
Authors: Underhill Anne B.
Published: July 2016

The observed spectral distribution from a star will, in principle, give information about the parts of the atmosphere from which the radiation comes. Most detailed theoretical studies assume that the atmosphere may be represented by plane parallel layers, but in the case of very strong absorption lines and weak continuous absorption, a case which is encountered in the ultraviolet spectral region of B stars, the radiation received from the centers of the lines may come from an entirely different part of the star than does that from the far wings of the lines or from the continuous spectrum. In the case of strong lines, because stars are three dimensional objects and because a field of motion may occur in the outermost part of the atmosphere, the appearance of the ultraviolet line spectrum may be poorly predicted using the hypothesis of stationary plane parallel layers.

Some numerical examples are presented demonstrating that with the UV resonance lines the opacity in the centre of a line may exceed the continuous opacity by a factor 106–108. A summary is given of the chief factors which should be taken into account in any theory of line formation when the hypothesis of LTE is not valid. A detailed description of the interactions between radiation and matter which can occur is necessary. Some examples of the distribution in energy of the lower energy levels of the ion are presented for typical ions of interest. This distribution and the presence of metastable levels are important factors in determining the significance of non-LTE physics. The paper concludes with remarks indicating that ultraviolet spectra of stars should be obtained with a spectral purity of at east 0.1 Å if progress is to be made in understanding the physical state of stars.
Possibility of fluorescence phenomena in the ultraviolet spectrum of symbiotic stars and long period variables
Authors: Swings J. P. , Swings P.
Published: July 2016

We discuss essentially the cases where molecular fluorescences may be excited by Lyman α and other strong discrete ultraviolet emissions, including lines beyond the Lyman limit. The stars involved are the symbiotic objects and the long period variables. The molecules are H2, N2, O2, NO and CO which have their resonance systems in the ultraviolet.
Resonance lines in the solar chromosphere
Authors: Lemaire P.
Published: July 2016

Stigmatic balloon spectra of the Sun in the vicinity of 2800 Å were obtained on September 22, 1968 and April 30, 1969. We compare the observed profiles of the H and K lines of ionized magnesium with the computed profiles of Athay and Skumanich and of Dumont. The discrepancy between observed and computed profiles of the Mgii lines is considerable. It is shown that this is a general fact for all chromospheric resonance lines of abundant elements. A brief review is given of different interpretations of this discrepancy.
Interstellar lines other than hydrogen
Authors: Herbig G.H.
Published: July 2016

I would like to extrapolate beyond the present state of interstellar line spectroscopy toward the next generation of satellite-borne equipment, but with due recognition of the fact that more work still has to be done from the Earth's surface.
Lyman-α radiation from nebular objects
Authors: Panagia N. , Fulchignoni M.
Published: July 2016

For a simplified model of a gaseous nebula, that is spherical, isothermal, homogeneous and composed of pure hydrogen, the amount of Lyman-α radiation emitted from the surface of the nebula is evaluated for various physical conditions. The problem of observability of the Lyman-α emission line is examined, taking into account absorption by dust and by interstellar neutral hydrogen.
Peculiarities of mm and cm radiowave propagation in the Venus atmosphere
Authors: Kroupenio N. N.
Published: July 2016

The total vertical absorption of mm and cm radiowaves in the Venus atmosphere is calculated from direct measurements of temperature, pressure and chemical composition, provided by the automatic interplanetary stations Venera-4, Venera-5 and Venera-6. The results are in good agreement with radar measurements of Venus and with extrapolations of direct measurements of temperature and pressure. The data fit a model with surface pressure 90 atm and a water vapor content of a few milligrams per liter. Vertical radiowave attenuations at various wavelengths are computed.
A new short-wavelength carbon dioxide band in the spectrum of Venus
Authors: Owen T. , Mason H. P.
Published: July 2016

In attempting to resolve the CO2 band at 7159 Å identified in the spectrum of Venus by Spinrad (1962), we discovered a new band at 7105 Å. Both bands are fully resolved on our spectra and tentative J numbers have been assigned to the rotational lines. In both cases, the P branch appears to be anomalously weak. The 7159 Å band has been observed in the laboratory (unresolved) by Herzberg and Herzberg (1953) at path lengths on the order of 55 km atm. To our knowledge, the 7105 Å band has not been recorded previously. Following the predictions of Herman (1948) the two bands are given the assignments 5v3 + 2v2 + v1 (7159 Å) and 5v3 + 2v1 (7105 Å). An unsuccessful attempt was made to find the third member of this triad, 5v3 + 4v2. In view of the very large amount of carbon dioxide apparently required to produce these absorptions, further study in the laboratory and at the telescope is encouraged.
Vegetative life on Venus? or investigations with algae which grow under pure CO2in hot acid media and at elevated pressures
Authors: Seckbach Joseph , Libby W. F.
Published: July 2016

Experiments are described with algae grown in a new environment of pure CO2under pressure and in an acidic nutrient medium at elevated temperatures. One species found in hot-springs was observed to grow. If the planet Venus has acidic polar seas as we suggest, they may harbor photosynthetic life.
Relative elevation differences revealed by near infrared CO2 bands on Mars
Authors: Woszczyk Andrzej
Published: July 2016

High dispersion spectroscopic observations of Mars, carried out with the new 107-inch and 82-inch Struve telescopes at McDonald Observatory, were used for detection of relative elevation differences on the surface of Mars. The dispersion of the spectra was 4.4 Å/mm for the 0.87 CO2 band and 3.5 Å/mm for the CO2 bands in the 1 μ region. Spatial resolution during the 1969 opposition was about 20° by 10° for 0.87 μ and 15° by 15° on the planet for the 1.03 μ and 1.05 μ bands. The results are shown in Tables I, II, III and Figures 2 and 3. The observed differences in elevation are on the order of 10 km, which is in good agreement with the latest radar measurements of the topographic features on the Martian surface.
A report on Martian atmospheric water vapor near opposition, 1969
Authors: Little S. J.
Published: July 2016

Little variation in Martian atmospheric H2O abundance was observed during three months prior to the 1969 opposition.
Cloud activity on Mars near the equinox: Comparison of the 1937 and 1969 oppositions
Authors: de Vaucouleurs G.
Published: July 2016

Four classes of manifestations of cloud activity observed in 1937 and 1969 near the autumn equinox of the northern hemisphere (165°< Ls < 192°) are discussed: (1) formation of the north polar haze cap, (2) unusual cloud systems on the disk, (3) recurrent or persistent cloud activity at the sunset limb, (4) clouds seen in projection above the sunrise terminator.
Variations in the color of jupiter
Authors: Hopkins Neil B. , Irvine William M.
Published: July 2016

Observations of Jupiter by multicolor photoelectric photometry in 10 narrow bands between 3150 Å and 1.06 μ and in UBV showed a brightening for shorter wavelengths in 1965 relative to 1963. An opposite effect occurred for the band at 7300 Å. These results are consistent with observed activity in the Jovian atmosphere. No obvious correlation could be found between brightness fluctuations and longitude of the central meridian, indicating that the activity was uniform in longitude or occurred on time scales short compared to a month.
The spectral characteristics and probable structure of the cloud layer of Saturn
Authors: Teifel V. G. , Usoltzeva L. A. , Kharitonova G. A.
Published: July 2016

Spectrophotometric (photographic and photoelectric) measurements of the intensity of CH4 absorption bands at 6190 and 7250 Å over different regions of Saturn's disk show an increase in intensity toward the poles and a decrease toward the equatorial limb. In the bright equatorial belt of Saturn the methane absorption is about 25–28% less than in the south temperate belt (latitude about −20°).

Absolute photoelectric spectrophotometry of Saturn's disk gives a value for the single-scattering albedo of the aerosol particles at λ 6200–6500 Å at the center of the disk. Calculations of the curves of growth for the absorption lines formed in the thin gas and in the cloud layer were made and the comparison with observations of Jupiter and Saturn lead to the mean value of the volume scattering coefficient of the aerosol layer σa < 5 × 10−6 cm−1. In the equatorial region of Saturn σa is larger than in the temperate region by a factor 1.3 to 1.8.

The models of Saturn's atmosphere that fit well the observational data preclude the condensation of methane. An aerosol layer of ammonia is more probable in the atmosphere of Saturn. Calculations of the distribution of the ammonia aerosol volume density (Qa) give Qa ≃ 10−9 to 10−7 gm/cm3 for relative abundances of ammonia A = 10−6 to 10−4. Observational estimates of Qa derived from the values of σa give Qa < 10−9 gm/cm3. Apparently Saturn's atmosphere departs from conditions of ordinary convection.

Some very interesting variations in the spectral reflectivity of the different regions of Saturn are observed, especially in the ultraviolet. These data, as well as a systematic study of the methane absorptions in the near infrared strong bands are needed in future studies of Saturn's atmosphere.
Gamma-Ray Spectrometry in the Energy Range 0.5–5 MeV
Authors: Albernhe F. , Doulade C. , Martin I. M. , Talon R. , Vedrenne G.
Published: July 2016

A stilbene scintillator detector allowing gamma-ray spectrometry in the range 0.5–5 MeV is presented. A complete elimination of charged particles is obtained by a plastic scintillator anticoïncidence jacket. Separation of gamma rays from neutrons is made by pulse shape discrimination technique with over 99% efficiency. This detector which has a 4 π field of view has been made as light as possible to avoid perturbation due to secondary production in the apparatus. The correction of the edge effects and the method of conversion from experimental Compton electron spectrum to gamma-ray spectrum are explained.

Results from balloon launchings at three latitudes (Kourou Guyana: 10 N, Aire sur l'Adour: 46°N and Oboziersky U.S.S.R.: 62 °N) are briefly presented. The detection possibility with balloons of galactic gamma rays at equatorial latitude is shown. The atmospheric part of the flux at the equator is deduced from the measurements at higher latitudes, (46 °N and 62 °N) where the galactic component is of negligible importance. Assuming a power law spectrum and after correction of the atmospheric absorption we obtain for the galactic spectrum the expression dN/dE = 1.1 × 10−5E−1, 2 photons/cm2 s sr keV. This spectrum agrees with the results of ERS 18 satellite given by Vette et al. showing an excess of flux for energies higher than 1 MeV.
Gas-Čerenkov Detector for 10 to 100 MeV Gamma Rays
Authors: Helmken H. , Hoffman J.
Published: July 2016

A gas-Čerenkov detector sensitive to gamma radiation above 10 MeV is currently undergoing final testing. The detector relies on the conversion and Compton scattering of gamma rays in a plastic scintillator and detecting the resulting electrons via the Čerenkov light they emit in a 2-m propane-gas column. Spectral information can be attained by varying gas pressure during the flight. The present detector is approximately 34″ in diameter, 91″ in length and weight 450 lb. At 20 MeV, an angular resolution of 6° half angle is expected. With an efficiency of 1 to 2%, a 10 hr balloon-borne system should achieve a point-source sensitivity of approximately 5× 10−5 photon cm−2 s−1 above 20 MeV. A satellite version of the detector is expected to have a sensitivity of approximately 1.3 × 10−5 photon cm−2 s−1 above 10 MeV for a 1-month galactic-plane scan mode. (Helmken and Hoffman, 1970.)
A Focusing Collector for Long Wavelength X-Ray Astronomy
Authors: Yentis D. J. , Angel J. R. P. , Mitchell D. , Novick R. , Vanden Bout P.
Published: July 2016

One of the outstanding problems in X-ray astronomy is the detection and understanding of a number of important phenomena that are expected at photon energies in the range from 100 eV to 1000 eV. One expects to be able to detect interstellar matter in both absorption and emission. It is of critical importance to cosmology to determine the spectrum, isotropy and intensity of extragalactic radiation in this energy region. It is also expected that a large number of discrete sources with temperatures in the range from 105K to 106K will be detected. Such sources could result from neutron stars that are cooling or from the accretion of interstellar matter onto condensed objects. Matter falling into ‘black holes’ may be heated sufficiently to be detectable at long X-ray wavelengths. Extended objects, such as the Cygnus Loop and the Magellanic clouds, are known to be luminous at low X-ray energies (Grader et al., 1970; Gorenstein, 1970); other such objects are almost certainly present. There may be local sources of diffuse radiation. Finally, it should be possible to detect X-ray zodiacal light.
Glancing Incidence Optics for X-Ray and Ultraviolet Astronomy
Authors: Underwood J. H. , Neupert W. M. , Hoover R. B.
Published: July 2016

Glancing incidence telescopes of the kind first described by Wolter have now been physically realized, so that it is now possible to obtain high resolution images of celestial objects at all wavelengths greater than about 3 Å. In this paper we shall describe two such instruments: the GSFC-MSFC X-ray telescope for the Apollo telescope mount uses Wolter type 1 optics and is capable of forming images of the sun in the 8–70 Å region with spatial resolution of the order of one arc second. The GSFC extreme ultraviolet spectroheliometer for OSO H uses type 2 optics and can obtain images of the Sun in spectral lines in the 170–400 Å region with a spatial resolution of about ten arc seconds. Theoretical (ray trace) and laboratory data on these systems will be presented.
The use of A Michelson Interferometer on a Coarsely Stabilized Spacecraft to Obtain High Resolution (0.1 Å) over 1300–3300 Å
Authors: Clark D. D.
Published: July 2016

The spectral resolution of the prism or grating spectrograph depends on its angular dispersion which, in a space environment, implies that resolution also depends on the accuracy of pointing of the space platform.
A Rocket Payload Using Cassegrain-Echelle Optics with Image Intensification for High Resolution Ultraviolet Stellar Spectroscopy
Authors: Burton W. M. , Reay N. K. , Shenton D. B. , Wilson R.
Published: July 2016

A description is given of a rocket payload designed to record high resolution ultraviolet stellar spectra using the star-stabilised ‘Skylark’ rocket vehicle. The system consists of a 35 cm aperture f/12 Cassegrain telescope and a spectrometer in which the high spectral dispersion of an echelle grating is crossed with that of a plane grating to separate the echelle orders. The spectrum is focussed onto an electrostatic image intensifier tube, the fibre optic faceplate of which is coated with sodium salicylate to give ultraviolet sensitivity. Photographic film is used to record the two dimensional spectrum array with a resolving power λ/dλ ≃ 104 between 1200 Å and 3000 Å. Efficiency measurements of components indicate that the photometric efficiency of the entire system will allow spectra to be recorded for early-type stars which are brighter than mr ≃ 5.
Rocket Experiment by Electronic Camera for Studying the Metallic Discontinuities in the Ultraviolet Spectrum of ‘A’ Stars
Authors: Combes M.
Published: July 2016

1.

Ultraviolet spectra (1400–1800 Å) of Ap, Am and normal A stars are needed by F. Praderie, R. Bonnet and R. Cayrel.

The spectral resolution has to be nearly 1 Å. Accurate relative photometry (5%) and absolute calibration (30–50%) are required.

A rocket experiment, proposed to ESRO by M. Combes and P. Felenbok is planned for launch in 1972.

2.

As neutral silicon and magnesium are very efficient ultra-violet absorbents, A stars ultraviolet fluxes are very faint (Praderie, 1968).

Then a very luminous optical set-up and a high efficiency receiver have to be used. A 30 cm in diameter concave objective grating is associated with a Lallemand electronic camera. The grating (2000 //mm; //l) is holographically made (Labeyrie, 1969). The electronic camera is electrostatically focussed. A semi-transparent solar-blind CsL photocathode is used (Carruthers, 1966).

3.

A little mirror, placed against the grating and forming a direct view of the sky, permits to establish an absolute wavelength scale.

During the fly, before and after stellar observations, a little concave mirror mounted into the opening side-door is used to form on the photocathode a spectrum of a Deuterium calibrated lamp. Two photomultipliers, one on each side of the electronic camera, control the lamp stability.

The complete mounting is calibrated in the laboratory using a thermopile as reference, before the launch and after the recovery of the waterproof payload.

4.

The chosen stars are the brightest Ap and Am stars: α Dra (Ap; mv = 3.64; equivalent type A 0) and α2 Lib (Am; mv = 2.75; equivalent type A3-A7).

It seems to be possible to obtain spectra (1400-1800 Å) of the Ap star with a spectral resolution of 1 Å and a signal to noise ratio better than 40. But at a pinch one may accept a resolution of 2 Å and a signal to noise ratio of 15 for the shortest range of the Ap star spectrum.
Integral Image Tube-Optical Systems for the Far UV
Authors: Chincarini Guido
Published: July 2016

An important feature of observations made outside the atmosphere from manned or unmanned spacecrafts is the reliability and ease of operation, speed and accuracy in the collection of data. A good compromise including the above features is the development of image tube techniques in skilfully matching optics and electronics.
The Wall-Stabilized Hydrogen Arc as a Radiation Standard in the Vacuum UV
Authors: Wiese W. L.
Published: July 2016

Extensive calculations of the radiative emission of an atmospheric pressure hydrogen arc in the temperature range from 8000 to 15000 K have been undertaken, which show that a partly ionized hydrogen arc plasma may serve as an intense and accurate spectral radiation standard in the ultraviolet. The principal features of the spectrum are: Between 1215 Å and 3600 Å the hydrogen arc emits only continuous radiation, dominated by the Balmer recombination continuum. Between 1215 Å and 930 Å the lower members of the Lyman series appear strongly Stark-broadened and optically thick in their central parts. The higher Lyman lines merge into a quasi-continuum, which leads into the very strong Lyman continuum. Between 930 and about 400 Å the continuum is optically thick, i.e., it represents blackbody radiation at typical arc temperatures of 12000 to 15000 K.
New Results and Techniques in Space Radio Astronomy
Authors: Alexander J. K.
Published: July 2016

The first long wavelength radio astronomical observations from above the ionosphere were performed in the early 1960's using very short antennas on both sounding rockets and satellites. Although these exploratory measurements were sometimes troubled by perturbations arising in the local plasma enivronment and by spacecraft interference, they did develop the fundamental information and techniques on which to build more sophisticated low frequency radio astronomical systems. The first spacecraft designed specifically and exclusively for radio astronomical studies, Radio Astronomy Explorer 1, was launched on July 4, 1968. It carries two gravity-gradient stabilized, 229-m, travelling-wave V-antennas, a 37-m dipole antenna, and a number of radiometer systems to provide measurements over the 0.2 to 9.2 MHz frequency range (λ = 33 to 1500 m) with a time resolution of 0.5 sec and an absolute accuracy of about 25%. Although the observations may seem crude in some cases, when compared with those of ground-based telescopes, the RAE has afforded substantial improvement over the capabilities of the early flight experiments. Through the study of solar radio bursts down to 0.2 MHz, we are getting new information on the density, plasma velocity, and dynamics of coronal streamers out to distances of greater than 50 R⊙. From galactic continuum background maps at frequencies around 4 MHz, we are getting new information on the distribution of the ionized component of the interstellar medium. Cosmic noise background spectra measured down to ~ 0.5 MHz are providing new estimates of the interstellar flux of cosmic rays, of magnetic fields in the galactic halo, and of the nature of radiation from distant extragalactic radio sources.

A second RAE spacecraft is now being constructed for launch into a lunar orbit. This satellite will permit radio astronomical measurements at frequencies down to 30 kHz (λ = 10 km), will facilitate the use of the moon as an occulting disk for source position measurements, and will provide new information on the cislunar noise environment required to assess the feasibility of future lunar radio observatories. Studies are in progress on the feasibility and application of orbiting radio interferometers (baselines up to 5 km) and large orbiting filled-aperture telescopes (diameter ~ 1 km).
Les relations entre les mouvements du pole et les fluctuations de la vitesse de rotation de la Terre
Authors: Melchior Paul
Published: July 2016

On expose comment on peut tenter une ample synthèse des résultats d'observations astronomiques telles que celles du mouvement du pôle et des fluctuations de la vitesse de rotation de la Terre avec des observations de caractère purement géophysique: les marées terrestres, la circulation atmosphérique générale, le retrait progressif des glaciers, etc.

On ne peut espéer donner dès à présent une conclusion à chacun des problèmes soulevés par la confrontation de ces données si diverses et l'on relèvera plusieurs contradictions. L'effort accompli dans le cadre de l'Année Géophysique permettra peut-être de lever certaines d'entre-elles et de parfaire la synthèse évoquée ici.
Geodetic constants and the motion of the Moon
Authors: Cook A. H.
Published: July 2016

The author discusses the set of constants required to describe the external gravitational field of the Earth : a set of form factors and two scale factors. Some problems in relating the external field as derived from the motions of satellites to the quantities observed at the surface are mentioned. The fondamental parameters cannot be derived from the data without a knowledge of other astronomical constants, and it is shown how a general adjustment of data of different origins can be made. The results enable suggestions to be made about the way in which new conventional values of these parameters should be chosen.
Constants related to the Earth and Moon
Authors: Jeffreys Harold
Published: July 2016

The author discusses various determinations of zonal and tesseral harmonics of the Earth's gravitational field, the values of the solar parallax, and the constants related to the figure of the Moon and its motion.
Astronomical and “astrodynamical” values of constants and ephemeral data
Authors: Herrick Samuel
Published: July 2016

The author comments upon the different needs of the astronomical constants in ephemeris work and space trajectory computations.
Some recent studies of nutation in the U. S. S. R.
Authors: Fedorov E.P.
Published: July 2016

The author compares amplitudes of the main terms of nutation as derived from various theories with the observed values. He also reports on the discovery, by Popov, of a term in the variation of latitude, with a period slightly shorter than a sideral day.
The precessional constant, parameters of solar motion and galactic rotation in the FK 4 system
Authors: Boshniakovich N. A.
Published: July 2016

In this paper, an investigation is made of the changes in the constant of precession, parameters of solar motion and of galactic rotation, caused by the transition from the FK 3 to the FK 4 system.
On the compatibility of the recent solar parallax results from radar echoes of Venus with the motion of Eros
Authors: Rabe Eugene
Published: July 2016

The author investigates whether the adoption of a value of the solar parallax determined by radar measures would permit an acceptable representation of the observations of Eros. The solution he obtaines leaves important residuals and leads to a rather unlikely value for the mass of Mars.
The topology of the third integral
Authors: Barbanis B.
Published: July 2016

In this paper a three-dimensional “integral surface” is described, which is the projection of the section of the energy integral by the third integral. The unperturbed frequencies are assumed to have an irrational ratio, or ratio 2:1. This surface contains the orbits whose initial points are on it; thus the general characteristics of the orbits are explained.
Averaging methods in celestial mechanics
Authors: Kyner W. T.
Published: July 2016

The purpose of this paper is to study the relationships among the classical Delaunay theory, the Diliberto periodic surface theory, and the Krylov-Bogoliubov method of averaging. It is shown that the von Zeipel simplification of the Delaunay method and the canonical method of averaging produce the same second order approximations. Furthermore, it follows from the existence of a formal expansion of the von Zeipel determining function that if a monotonicity condition is satisfied, then there exists a formal expansion of a family of periodic two surfaces.
Les potentiels isocinetiques
Authors: Nahon F.
Published: July 2016

Construction de tous les potentielsU(x,y) qui admettent une famille de trajectoires constituée des lignes de niveau deU.On trouve deux classes principales de solutions: les lignes de niveau circulaires et les lignes de niveau spirales; et on étudie un cas d'integrabilité des équations du mouvement dans un potentiel de la deuxième classe.
Cluster models and the escape of stars
Authors: King I. R.
Published: July 2016

From an assumed velocity distribution spatial densities can be calculated, and solution of Poisson's equation then leads to a complete cluster model. A number of such models now exist which give density laws close to those actually observed in clusters. These models can be used to calculate the rate of escape of stars, which turns out to depend very strongly on the central concentration of the cluster. The dependence on stellar mass is small.
The gravitational field of the Galaxy
Authors: Schmidt M.
Published: July 2016

The rotation curve in the plane of the Galaxy out to the Sun and the forceKznear the Sun yield relative gravitational potentials through certain regions in the Galaxy. A mass model is probably the best means to determine the absolute potentials and to interpolate the field throughout the rest of the Galaxy. A new mass model of the Galaxy is described briefly.
Galactic orbits of stars
Authors: Woolley Richard
Published: July 2016

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.
On the structure of stellar clusters after relaxation
Authors: Hoerner S. von
Published: July 2016

The evolution of globular clusters is studied by means ofN-body problem calculations with 16 and 25 stars for time intervals up to 40 times of relaxation. It is found that within two to four times of relaxation all clusters with different starting conditions approach an isothermal polytrope and a Maxwellian distribution of velocities. In much longer times the deviations from an isothermal polytrope and a Maxwellian distribution of velocities become very important. A cusp is formed near the center of the cluster, but no central core can be distinguished. There is an excess of small and large velocities; the excess of high velocities is due to the formation of close pairs near the center. The escaping stars are fewer by a factor of 5. The virial theorem and Chandrasekhar's time of relaxation are approximately verified. Some other results are also discussed.
Periodic Trojan orbits in the elliptic restricted problem
Authors: Rabe E.
Published: July 2016

As previously shown the generally non-periodic librations about the equilateral points of the plane elliptic restricted problem depend on three frequencies. After elimination of the short-period oscillations, the solutions depend on the libration frequencynand the mean angular motionNof Jupiter. Whenn/Nis commensurable the librations become periodic. One periodic solution corresponds to the actual Trojans, but additional planar solutions exist also with periods equal to multiples of the basic period. For some specific values of the eccentricityethese solutions are accompanied by an associated sequence of non-planar periodic solutions. The values ofedepend slightly on the inclinationi.
Convergence in planetary theory and the selection of the constants
Authors: Danby J. M. A.
Published: July 2016

In planetary theory certain traditions have arisen with regard to the selection of numerical values for certain constants. These constants can be related to the mean reference orbit that is perturbed to give the true orbit. It is argued here that the only criterion that is important in choosing this mean orbit is that its mean sideral motion should be as near as possible to that of the true orbit. Other criteria are unimportant in the sense that they cannot be guaranteed to lead to any increase in the accuracy of the theory.
Current status of special planetary and lunar theories and ephemerides
Authors: Duncombe R. L.
Published: July 2016

An examination of some specialized lunar and planetary ephemerides has revealed inconsistencies in the adopted planetary masses, the presence of non-gravitational terms, and some outright numerical errors. They should be considered of temporary usefulness only, subject to subsequent amendment as required for the interpretation of observational data.
Artificial satellite orbit computations
Authors: Sconzo P.
Published: July 2016

In this paper an orbit computation program for artificial satellites is presented. This program is operational and it has already been used to compute the orbits of several satellites.

After an introductory discussion on the subject of artificial satellite orbit computations, the features of this program are thoroughly explained. In order to achieve the representation of the orbital elements over short intervals of time a drag-free perturbation theory coupled with a differential correction procedure is used, while the long range behavior is obtained empirically. The empirical treatment of the non-gravitational effects upon the satellite motion seems to be very satisfactory. Numerical analysis procedures supporting this treatment and experience gained in using our program are also objects of discussion.
The motion of a lunar orbiter
Authors: Kozai Y.
Published: July 2016

The motion of an artificial satellite around the Moon is much more complicated than that around the Earth, since the shape of the Moon is a triaxial ellipsoid and the effect of the Earth on the motion is very important even for a very close satellite.

The differential equations of motion of the satellite are written in canonical form of three degrees of freedom with time depending Hamiltonian. By eliminating short-periodic terms depending on the mean longitude of the satellite and by assuming that the Earth is moving on the lunar equator, however, the equations are reduced to those of two degrees of freedom with an energy integral.

Since the mean motion of the Earth around the Moon is more rapid than the secular motion of the argument of pericentre of the satellite by a factor of one order, the terms depending on the longitude of the Earth can be eliminated, and the degree of freedom is reduced to one.

Then the motion can be discussed by drawing equi-energy curves in two-dimensional space. According to these figures satellites with high inclination have large possibilities of falling down to the lunar surface even if the initial eccentricities are very small.

The principal properties of the motion are not changed even if plausible values ofJ3andJ4of the Moon are included.

This paper has been published in Publ. astr. Soc.Japan15, 301, 1963.
Phase Calibration of the Proposed Millimeter Array
Authors: Holdaway M. A.
Published: July 2016

The Millimeter Array (MMA) is proposed to operate on baselines of up to 3 km at frequencies up to 350 GHz. Since no operating interferometer can indicate the expected phase stability on such baselines on high, dry sites, NRAO has undertaken a site survey, measuring the opacity and estimating the phase stability on baselines ranging from about 100 m to 5 km with a tipping radiometer. Radiometers have sampled the atmospheres at South Baldy, NM, and Springerville, AZ, and NRAO has recently started taking data at the 12,200 foot VLBA site on Mauna Kea.
The Very Long Baseline Array
Authors: Napier P. J.
Published: July 2016

The VLBA is a new radiotelescope dedicated to research in astronomy and astrometry/geodesy using the techniques of VLBI. The array comprises ten 25 m diameter reflector antennas located so as to give optimum coverage of baselines up to 8600 km. Instrumentation provided at each antenna includes receivers for nine frequency bands between 327 MHz and 43 GHz, a hydrogen maser frequency standard and a tape recorder system capable of a peak data rate of 512 Mb/s and unattended operation for a day recording at 128 Mb/s. The antennas are controlled and monitored by a single operator located in the Array Operations Center (AOC) in Socorro, New Mexico. The AOC also houses the 20 station correlator which processes the data recorded at the antennas.
Recent Results from the VLBA
Authors: Diamond P. J. , Beasley A. J.
Published: July 2016

The VLBA construction phase is now over and in the spring of 1993 it is hoped that full VLBA observing can begin. However the VLBA antennas have been operational for some time and several astronomy programs have been run on them. Below we shall present some of these latest results.
The COAST Interferometer
Authors: Cox G. C.
Published: July 2016

The Cambridge Optical Aperture Synthesis Telescope (COAST) [1] will be the first instrument of its kind to exploit the techniques of aperture synthesis and closure phase to produce very high resolution (one milliarcsecond) optical images. The instrument will consist of four identical independent mobile 40 cm telescopes, and an optical building incorporating the path compensators and the fringe and acquisition and auto-guider detector systems. The present status is; there are three operational telescopes on site with two fully functional path compensator trolleys, an acquisition and auto-guider system capable of controlling up to four telescopes, correlator and a fringe detector system.
The Micro-Precision Interferometer Testbed Instrument Design
Authors: Hines B. , Neat G. , Colavita M.M. , Calvet R. , Sword L.
Published: July 2016

The Micro-Precision Interferometer Testbed is essentially a space-based Michelson interferometer suspended in a ground-based laboratory. The purpose of the testbed is to serve as a proving ground for technologies needed for future space-based missions requiring low-vibration environments. A layered control architecture, utilizing isolation, structural control, and active optical control technologies, allows the system to achieve its vibration attenuation goals.

This paper focuses primarily on the interferometer instrument design for the testbed and the systems-level tradeoffs between the instrument and other systems due to the fact that the interferometer is on a large, lightly damped, flexible structure rather than on the ground. The testbed is designed to be a fully functioning interferometer spacecraft and makes use of flight-like hardware where possible, including an external star simulator, an attitude control system, fringe detection and tracking systems, delay lines, pointing control, laser metrology systems, and computers and electronic subsystems. The engineering decisions that led to the current instrument configuration are presented and explained.
Radio Source Variability as a Tool for Very High Resolution
Authors: Shapirovskaya N. , Slee O. B. , Hughes P. , Tsarevsky G.
Published: July 2016

If flux density variability is intrinsic to extragalactic sources, then the shortest time scale of the variability yields an extremely high angular resolution. There is, however, good evidence that some of the variability is due to refractive scintillation in our galaxy's interstellar plasma turbulence. The effect, initially discovered at low radio frequencies, is here shown to extend into the GHz band, which, up to now, has been assumed to display only the intrinsic variability. We conclude that further study in both the intermediate and high frequency bands needed to separate the intrinsic and extrinsic components of variability.
Latest Technical Developments at the Infrared Spatial Interferometer
Authors: Bester M. , Degiacomi C.G. , Danchi W.C. , Greenhill L.J. , Townes C.H. , Reisinger A. , Weaver J.
Published: July 2016

Recent upgrades of the Infrared Spatial Interferometer are described. These provide improved sensitivity, precision and convenience of measurement. Analysis of phase fluctuations within the interferometer as well as in the atmosphere above indicates that popular simple atmospheric models need to be refined. Results of stellar observations are presented in another paper (cf. Danchi et al., in these Proceedings).
Results with the Extended MERLIN
Authors: Anderson B. , Davies R. D.
Published: July 2016

A major enhancement of MERLIN completed in 1992 has led to a transformation of its capabilities. The seventh telescope added to the array is a 32-m telescope at Cambridge which provides high sensitivity on all the longest baselines where extra collecting area is especially beneficial. The 32-m telescope is a shaped primary-Cassegrain configuration which achieves an 80 percent aperture efficiency. A change from frequency to amplitude modulation in the microwave links increased the effective bandwidth from 9 to 30 MHz. This broadbanding enables the two hands of circular polarization to be transmitted simultaneously, each in a 15 MHz bandwidth. A further improvement in the system sensitivity was achieved by cryogenically cooling the low noise amplifiers in the front-end receivers.
Miyun 232 MHz Survey and Some New Imaging Techniques
Authors: Xizhen Zhang , Yijia Zheng
Published: July 2016

A new meter-wave survey of sky region north of declination +30° is carried out with the Miyun 232 MHz Synthesis Radio Telescope(MSRT). The instrument, observation and some new imaging techniques are briefly described in this paper. As first result, two 8° × 8° regions centred respectively at α : 00h41m, δ: 41°12′ and α: 07h00m, δ: 35°00′ were observed and reduced. On the average 4 – 5 sources per square degree are recorded with position accuracy of 5′ / S(Jy). The accuracy of flux determination is limited by background fluctuation which is about 30 mJy. The catalogue is complete for sources with flux larger than 0.25 Jy.
Near Infrared High Angular Resolution Observations of Stars and Circumstellar Regions by the Technique of Lunar Occultations
Authors: Chandrasekhar T. , Ashok N. M. , Ragland Sam
Published: July 2016

A program of High Angular Resolution observations of stars and their circumstellar regions using the technique of lunar occultations has been initiated at the 1.2 m telescope at Gurushikhar (24°39′ N, 72°47′ E), India. A liquid nitrogen cooled InSb detector based high speed Infrared photometer with millisecond data acquisition capabilities has been developed for the near Infrared region (1–5 μm) and eight occultations have been successfully observed in the K band (2.2 μm). The sources are (IRC No. -10578, +10013, +20034, +30094, +20190, +20200, +20073 and +00198. The diffraction pattern is clearly seen in all the observations. A convolution analysis involving the system frequency response, filter bandwidth and one dimensional source structure has been carried out to fit the data. System capability has been determined to be ~ 6 milliarcseconds.