bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Automatic Electronic Astrolabe
Authors: Tsubokawa Ietsune , Hokugo Shunro
Published: July 2016

The pendulum astrolabe with an electronic transit detector after the principle proposed by I. Tsubokawa has comparable accuracy to those of the Danjon astrolabe and P.Z.T. even in the field. After the same principle, an instrument for observatory use is being constructed, in which all observational processes are done automatically under the predetermined programs. The necessary mechanisms for automatic operation are as follows:

(1) Azimuth setting mechanism for respective stars observed.

(2) Mechanism which turn the telescope through 180° during the passage of a star near the mean altitude.

(3) Tracking mechanism in azimuth direction.

(4) Tracking mechanism in altitude direction.

(5) Read-out mechanism of the times of passages of a star on respective altitude circles.

Of these, the altitude tracking mechanism directly affects the observational accuracy. The rotation of a plane parallel glass compensates the diurnal motion of a star and keeps its image in the state of repose on the edge of a prismatic knife of the electronic detector. The rotating mechanism gives to the plane glass combined rotation of the two parts; the servo-system of the electronic detector and the system of generating the variable rotational velocity corresponding to the diurnal motion of a star. The extreme accuracy in the earth's atmosphere is expected.
Polar Wandering and Mantle Convection
Authors: Takeuchi H. , Sugi N.
Published: July 2016

According to the mantle convection theory, mantle materials come up to the surface of the Earth at the mid-oceanic ridge system, go off in two horizontal directions, and finally at the trench and orogenic belt system they return to the interior of the Earth. We assume no return flow in the deeper part of the mantle and calculate the change of products of inertia of the Earth due to the above mass transfer. The polar wandering thus calculated is towards the direction of about 90° east and its absolute value is about 0.9 × 10−2 s/yr.
Effect of the Change in the Geomagnetic Dipole Moment on the Rate of the Earth's Rotation
Authors: Yukutake Takesi
Published: July 2016

The electromagnetic coupling between the Earth's core and the mantle is studied when the geomagnetic dipole field varies periodically. The oscillation of the geomagnetic dipole moment with a period of 8000 years, its amplitude being 50% of the present moment, is capable of causing a fluctuation of 10−11 rad/s in the angular velocity of the mantle. The angular velocity increases with a decrease in the dipole moment.
On the Relation between the Rotation of the Earth and Solar Activity
Authors: Sugawa Chikara , Kakuta Chuichi , Matsukura Hideo
Published: July 2016

Solar activity may affect the rotation of the solid Earth by coupling between the lower neutral atmosphere and the solid Earth. It attacks directly the lower atmosphere in the non-axially symmetric mode and may trigger off variation of the amplitude of the annual terms in the polar motion. The indirect effect of solar activity may be associated with some proper oscillation of the atmospheric coupling with the ocean in the axially symmetric mode of the atmospheric motion. The shift of airmass along the rotating axis of the Earth corresponds well with the changes of the Earth's rotational velocity and the Chandler amplitude in the polar motion for long time variation.
UV and Radiofrequency Observations of Wolf-Rayet Stars
Authors: Johnson Hugh M.
Published: July 2016

Very few observations are available. Of early rocket work on γ Vel (Stecher and Milligan, 1962; Smith, 1967) the most detailed spectra are by Stecher (1968) in the range λ 1200–3100 Å and by Carruthers (1968) in the range λ 1050–1216 Å. West's (1971) spectrum of γ Vel with the OAO-2 spectrometer (Code et al., 1970) in the range λ 1050–2000 Å appears to be somewhat different from Stecher's. Comparison must await full details.
Nuclei of Planetary Nebulae
Authors: Smith Lindsey F.
Published: July 2016

In 1969 Aller and I collected information about the spectra of emission-line nuclei of planetary nebulae. (See also Aller, 1967, for classification of both emission and absorption spectra.) We classified them and compared them to the spectra of Population I stars. Our idea was to follow this general classification by detailed observation and comparison of stars in each of the classes. Most of the detailed studies are not complete, but already the picture has changed from the way Aller and I saw it.
Evolutionary Aspects of Wolf-Rayet Stars
Authors: Paczyński B.
Published: July 2016

Problems related to Wolf-Rayet stars were recently reviewed by Underhill (1968) and were discussed at length during the symposium held at the Joint Institute for Laboratory Astrophysics in Boulder (Gebbie and Thomas, 1968). Therefore, I shall not review here the historical development of ideas, and I shall not give detailed references in those cases when all the information is available in the sources mentioned above. I shall discuss first those observational data that are most important for the understanding of the evolutionary status of these stars. Later I shall discuss the problem of the interior structure and the origin of WR stars. And finally theories of the driving force for the observed mass loss will be presented.
Introductory Talk for Session on Objective Prism Spectral Classification
Authors: Stephenson C. B.
Published: July 2016

Traditionally, introductory talks usually have either the function of justifying the meeting at which they are given, or of attempting to present some sort of overview of the whole subject, or sometimes both or neither. A meeting such as this one is generally in order when the field in question has for any reason been very active since the last meeting about it; and by that standard I should say that this symposium is indeed appropriate inasmuch as the field of spectral classification has surely been very active during the seven years since the last symposium on spectral classification and multicolor photometry. In the area of objective prism spectral classification, the last several years have not seen very much really new in the way of observing techniques or methods of analysis that I know of, at least in comparison with some other fields; but they have certainly seen a great deal of astronomy done.
Two-Dimensional Classification of the HD Stars
Authors: Houk N. , Cowley A.
Published: July 2016

The major project of assigning spectral and luminosity classes to the Henry Draper stars south of +30° is underway. The high-quality objective-prism plates have been taken with the Michigan Curtis Schmidt telescope at Cerro Tololo Inter-American Observatory. The spectra, widened to .8 mm, have a dispersion of 108 Å mm-1 at Hγ. Plates exposed for 20m and for 4m + 1m yield classifiable spectra between 4 and 10 mpg.

Star identification is completely automatic, using a computer-generated plot to the Schmidt plate scale for each plate center. This plot, having the HD stars identified by number, is copied onto transparent material and placed under the Schmidt plate while the stars are visually classified.

Classification is being carried out by one person (N.H.) to maintain a uniform system. MK spectral standards of similar quality and density, also taken with the Schmidt, are continually referred to. Intercomparison of the new types with existing spectral types shows no systematic differences. However, the HD types themselves are systematically earlier in the range A to F.

Stars between the south celestial pole and δ = −55° are being classified first, with the first volume of results to be published late in 1973. It is expected that the catalogue of spectral types and remarks will be published in 6 volumes containing all HD stars south of +30°.

This research is being supported by the National Science Foundation.
Classification of Early Type Stars on the Dominion Astrophysical Observatory Photometric System
Authors: Morris S. C. , Hill G. , Walker G. A. H. , Thompson H. I. B.
Published: July 2016

A classification method has been developed for early–type stars observed on the Dominion Astrophysical Observatory photometric system. Two reddening-independent parameters, Q(35) and Q(38), are used. Q(35) is a measure of the Balmer discontinuity, while Q(38) is a measure of the strength of the upper members of the Balmer series. A preliminary calibration of Q(35) and Q(38) in terms of spectral types and luminosity classes is given, and applications to several groups of stars are shown.
The David Dunlap Observatory (DDO) Photometric System for Classification of Late-Type Stars
Authors: McClure R. D.
Published: July 2016

An intermediate bandpass filter system is described that is useful for classification of G and K stars in terms of effective temperature (spectral type), surface gravity (luminosity class), heavy element abundance, and interstellar reddening. The system measures the strength of the cyanogen band in the region shortward of λ4216, the break in the continuum at the G band, and a colour index in the λ4500–λ4900 region of the spectrum. The surface gravity parameter is independent of the cyanogen index, and the cyanogen band strength, after a surface gravity correction, is used as a measure of heavy element abundance.

Application of the system to the determination of the atmospheric parameters of open cluster giants, as well as of field stars, is discussed. The system has been used to isolate stellar populations among field stars without any prior knowledge of their distances. From observations on this system, the only open cluster found so far to have giants with stronger cyanogen band absorption than the Hyades giants is the intermediate age southern cluster NGC 2477.
Multicolor Photometry of the Galactic Cluster NGC 2362
Authors: Perry Ch. L.
Published: July 2016

U, B, V colors of CPD stars brighter than 12.m0 in the central region of NGC 2362. Color excess. Discussion of the distance modulus of the cluster.
Low Dispersion Spectrophotometry of Late Type Stars
Authors: Moreno H.
Published: July 2016

Low dispersion (slit 60 Å wide) spectrophotometric observations of late type stars have been made. The sample of stars observed cover from K0 to M8 and luminosity classes V to I.

A selection of these stars including each luminosity class and spectral type is being analyzed. The observed intensity distributions have been corrected for atmospheric extinction and have been normalized to a common maximum intensity. The resulting instrumental intensity distributions are being studied for the best parameters for spectral classification.
Information and Catalogues
Authors: Jaschek C.
Published: July 2016

The information used by scientists belongs to three basic types: (1) data, (2) procedures (techniques or description of instruments) and (3) theories and ideas. In what follows we shall consider only the first type of information, namely data. We will call ‘data’ all information related to or derived from observable quantities, like radial velocities, spectral types, color indices, etc.
Problems of Gaseous Motion Around Stars
Authors: Huang Su-Shu
Published: July 2016

A distinction is drawn between radial and tangential modes of ejection from stars, and the possible flow patterns are described. They are: expanding streams, falling streams, jet streams, circulatory streams, and gaseous envelopes. Motion around Be stars is discussed at some length, as a preliminary to studying more complicated flow in binary systems. The rotational velocity of the Be star is insufficient to form the ring. It appears likely that radial instability is temperature sensitive. Rings and disks in binary systems are discussed from the point of view of periodic orbits for particles within the gravitational field of such a system. The formation of these rings is discussed. The expected relation between rotational velocity of the ring and the orbital period is discussed. The relation of circumstellar streams to period changes is mentioned. Finally, the influence of magnetic fields on the circumstellar material and the system is discussed.
Pions in Neutron Star Matter
Authors: Sawyer Raymond F.
Published: July 2016

Arguments are given for pions becoming an important constituent of neutron star matter at densities greater than a critical density lying between 5 × 1014 and 1015 g cm−3. It is anticipated that this will lead to a substantial softening of the equation of state.
UHURU Results on Galactic X-Ray Sources
Authors: Tananbaum Harvey D.
Published: July 2016

Galactic X-ray sources studied by UHURU can be classified into several categories, including supernova remnants, transient or nova-like sources, Sco X-1 like sources, and pulsating sources. The latter are discussed in some detail with particular emphasis upon the characteristics of the periodic binary X-ray sources, Cen X-3 and Her X-1. It is suggested that all galactic X-ray sources (except S/N remnants) may be binary systems.
Hard Cosmic X-Ray Sources
Authors: Peterson L. E.
Published: July 2016

A review of the observational status of X-ray sources detected in the 20 ⋍ 500 keV range is presented. Of the approximately 115 sources listed in the March 1972 edition of the UHURU 2–6 keV sky survey catalog, about 15 sources have been studied in hard X-rays. Most of the data have been obtained from balloons, although the OSO-3, and more recently the OSO-7, have contributed. With the exception of CEN A, the SMC, and possibly M-87, all the sources detected at higher energies are galactic and heavily concentrated in the galactic plane. The Crab Nebula has been measured to about 500 keV in continuous emission and a component at the ⋍ 33 ms pulsar period comprising about 20% of the total emission has been detected to ∼10 MeV. Objects such as SCO-1 and CYG-2 are characterized by an exponential spectrum, which varies over a 10 min. time scale about a factor of two, and a flatter spectrum extending to above 40 keV which exhibits independent variability. Objects such as CYG-1 and possibly CYG-3 have a multi-component power law spectrum extending to over 100 keV, and may vary many factors over a period of weeks. Other sources generally not yet identified with optical or radio candidates, located in the Galactic Center and the Centaurus/Crux region also show considerable variability, and in one case may have been detected to nearly 500 keV. Only upper limits at about 2 × 10−4 photon (cm2 s keV)−1 in the 20–50 keV range exist for most supernova remnants and extragalactic sources.
‘Evolutionary’ Theories of the X-Ray Background
Authors: Rees M. J.
Published: July 2016

It is unclear whether evolutionary effects must be invoked to account for the intensity of the X-ray background, nor whether the background could all be due to unresolved X-ray sources of the types already known. Intensity fluctuations on small angular scales are probably on the threshold of detectability. Future studies of these fluctuations – with improved sensitivity – should help to elucidate the nature of the background. The interpretation of such studies is discussed.
The diffuse interstellar bands III: The situation in 1966
Authors: Herbig G. H.
Published: July 2016

Several possible identifications for the diffuse interstellar lines are reviewed. The strong correlation of diffuse-line strength and of interstellar extinction in the continuum, as well as the break in the extinction curve close to the wavelength of the strongest diffuse line (4430 Å), indicates that the absorber is closely associated with the solid particles. Possibly a molecule frozen on or in the grains may be responsible. Other possibilities considered include a negative ion with 2.8 eV as ionization limit, and free polyatomic molecules.
The Parkes survey of 21-cm line emission near the galactic equator
Authors: Kerr F. J.
Published: July 2016

A detailed 21-cm survey of the Milky Way in the longitude range 185° to 63° is described, and the objectives discussed. A preliminary study of some symmetry properties indicates that the line profile integrals, taken over velocities corresponding to locations outside the solar circle, are systematically higher on the southern-longitude (l11< 360°) side of the galactic centre.
Extragalactic 21-cm work at Nançay
Authors: Heidmann J.
Published: July 2016

The radiotelescope at Nançay has made its first test observations of extragalactic 21-cm radiation. The receiver is a correlation receiver using a hybrid junction. The main program aims at getting information on the overall properties of numerous faint galaxies. The number of channels is only 15; their width is 280 kHz = 59 km/sec, so that the line profile for a typical galaxy occupies about half the total passband of 4·2 MHz ≈ 900 km/sec.
A survey of recombination-line radiation from galactic H 11 regions
Authors: Mezger P. G.
Published: July 2016

This paper summarizes the results of observations of the hydrogen 109 α line at 5009 MHz in galactic H 11 regions.
Formation of the Galaxy
Authors: Lynden-Bell D
Published: July 2016

From observations it is deduced that the disk and halo were formed about the same time and that most of the previously gaseous Galaxy became stars then. Dimensional analysis indicates that the flattening of a galaxy is related to its energy,E, angular momentum,H, and mass,M, by the dimensionless number - 2EH2/G5M5. Emphasis is placed on the binding energy, -E, and the energy loss mechanisms of the proto-galaxy, with the aim of explaining Fish's relation -E∝M3/2.

Free-bound and free-free emission of hydrogen leads to rapid cooling of proto-galaxies, and dynamical collapse ensues, in which gravitational potential energy is converted into kinetic energy of collapse. As the system becomes flat, this energy is dissipated in violent shocks, behind which zones some 10 to 20 pc thick reach temperatures of 106·5°K and emit strongly in the X-ray region and the ultraviolet. If surrounded by more than a fraction of a gram per cm2, the X-rays will be trapped within the system and eventually converted into Balmer lines, which escape, and Lyman α, which is trapped. About half the total energy of collapse may be left in Lyman α, and it is possible that the system may bounce on this light energy.

The readily observed surface brightnesses of galaxies are related to surface densities by the relationship: magnitude 20 per (sec of arc)2= 1·5 gram cm-2, for an assumed mass-to-light ratio of 10.
Galactic magnetic-field models derived from Faraday-rotation data
Authors: Davies R. D.
Published: July 2016

The distribution of rotation measures for 86 sources suggests a two-component model for the magnetic field: a disk component directed towardl= 95°, and a component in the local spiral arm, directed alongl= 70° and 250°, with opposite senses above and below the plane. The latter may be due to a looped field in a cloud surrounding the Sun; its net flux is 3·5 micro-gauss.
Observations of the continuum near the galactic centre
Authors: Kerr F. J.
Published: July 2016

A continuum survey of the galactic-centre region has been carried out at Parkes at 20 cm wavelength over the areal11= 355° to 5°,b11= -3° to +3° (Kerr and Sinclair 1966, 1967). This is a larger region than has been covered in such surveys in the past. The observations were done as declination scans.
Cosmic rays in the Galaxy
Authors: Ginzburg V. L. , Syrovatskij S. I.
Published: July 2016

A summary is presented of our knowledge concerning the properties and origin of cosmic rays observed near the Earth. We discuss different conceptions of the origin of cosmic rays, including both galactic and metagalactic origins, and their relation to galactic structure. Our arguments favour a galactic rather than a metagalactic origin.
Measurement of interstellar extinction in emission line stars
Authors: Viotti R.
Published: July 2016

Usually selective interstellar extinction is derived by comparing the spectrum of a reddened star with an unreddened nearby star, preferably of the same spectral type. But in many cases this comparison is not possible, so that new methods have to be used.

A direct measure of this quantity is possible when a spectrum shows a number of emission lines as for the peculiar stars (novae, nova-like objects, symbiotic stars, etc.) and for nebulae. From a statistical point of view there are a small number of objects but they are of very high interest as far as stellar evolution is concerned.
Review of ultraviolet and visual continuum observations and comparisons with Models
Authors: Bless R. C.
Published: July 2016

This paper first briefly describes model atmosphere grids now available for comparison with observations. The recent recalibration of the absolute energy distribution of α Lyr substantially improves the agreement of models and observations in the visual. Temperature scales determined by various methods agree reasonably well except for the hottest stars. Recent ultraviolet results suggest that earlier observations of O- and B-type stars indicating large flux deficiencies were probably in error. However, late B- and A-type stars may emit less energy in the UV than that predicted by models which do not include the opacities caused by silicon, magnesium, and carbon.
Ultraviolet photometry of stars obtained with the Celescope experiment in the Orbiting Astronomical Observatory
Authors: Davis Robert J.
Published: July 2016

We have used the television photometers in the Celescope OAO experiment to measure the far ultraviolet brightnesses of several thousand stars, including parts of the constellations Draco, Lyra, Puppis, Vela, Taurus, and Orion; and the Moon. As of this date (22 July 1969), three of our four cameras continue to operate satisfactorily, and we are making measurements in additional star fields distributed throughout the sky. Our shortest wavelength band, which includes the Lyman α line of atomic hydrogen, provides information on the Earth's outer atmosphere, as well as on star brightnesses. The intensity of the Lyman α radiation from the geocorona is a maximum when the Sun is near the horizon as seen by the OAO, and a minimum when the Sun is in the nadir. The direction that the telescope points does not much affect the measured intensities.

Because of the heavy logistic problems of identification, calibration, and measurement for so many stars and because of the survey character of the program, the scientific interpretation of the results is, as expected, lagging the measurement program. However, one consistent picture beginning to emerge from our data is that our observed stars are about equally divided between those that fall within 0.5 magnitude of the predicted ultraviolet brightnesses and those that are significantly fainter than predicted. Most of the giant stars we observe exhibit these ultraviolet deficiencies. Since some of these giants are stars for which little or no interstellar reddening is predicted, we attribute the observed deficiencies to the stars themselves.

Many of the objects we observe do not have accurate ground-based published data regarding magnitude, color, and spectral type; new ground-based observations of these objects are required to ensure satisfactory interpretation of our results.
Chromospheric activity in red giants, and related phenomena
Authors: Deutsch Armin J.
Published: July 2016

Normal red giants of a given spectral type are shown to be heterogeneous with respect to the following chromospheric features: the Balmer absorption lines, the emission line at H∊, and the double-reversed emission lines at Caii H and K. These chromospheric lines are also shown to be strongly time variable, in at least some red giants, on a time scale of a few months or years. Other chromospheric features that require study lie in the infrared (Hei 10830), the near ultraviolet (Feii emission lines), and the vacuum ultraviolet.
Stellar-wind theory for O and B stars
Authors: Solomon Philip M.
Published: July 2016

The rocket-ultraviolet observations of strong Doppler-shifted absorption lines of Siiv, Civ, Nv and other ions in the spectrum of O and B supergiants clearly indicate a high velocity outflow of matter from these stars. The presence of moderate ionisation stages in the stellar wind is conclusive evidence that the flow cannot be due to a high temperature corona as is the case for the solar wind. It is shown that the driving mechanism for the hot-star mass loss is radiation pressure exerted on the gas through absorption in resonance lines occurring at wavelengths near the maximum of the star's continuum flux. In the upper layers of these stars the outward force per gram of matter due to the radiation pressure can greatly exceed the gravitational acceleration making a static atmosphere impossible.

The problem of a steady-state moving reversing layer is formulated and the solution leads to predictions of mass-loss rates as a function of effective temperature and gravity for all hot stars. These results are in substantial agreement with the observations.
Geochemical problems in the production of the Venus clouds
Authors: Sill Godfrey T.
Published: July 2016

Spectroscopic evidence is strong that the clouds of Venus are composed of ferrous chloride hydrate. At the surface of the planet it appears as though the vapor pressure of ferrous chloride may be quite low (10−6 atm), especially if such vapor is allowed to come to equilibrium with the other constituents of the Venus atmosphere. The formation of magnetite (Fe3O4) may be favored, and the spectrum of magnetite is shown in relation to the spectrum of the Venus cloud cover. The presence of ferrous chloride in the upper atmosphere may be due to a non-equilibrium condition.

The spectrum of volatiles, such as the halides of mercury, are considered vs the albedo of Venus. The presence of these volatiles seems incompatible with the spectroscopic evidence. It is suggested that the planet has been depleted of its volatiles, as it has been depleted of its water.
Mie scattering and the Martian atmosphere
Authors: Egan Walter G. , Foreman Kenneth M.
Published: July 2016

It has been suggested that the discrepancy between radio occultation determinations of the Martian atmospheric surface pressure (3.8 to 7 mb) and those deduced from optical polarization measurements and a simple Rayleigh atmosphere model (about 10 mb) are the results of sub-micron sized aerosols in the Martian atmosphere. Based on observed viewing angle dependence of the polarization of the Martian disk in the visual range, a Mie scattering analysis has been made utilizing the measured complex index of refraction of limonite and bulk solid CO2. The results of this study indicate that limonite aerosols alone are unsatisfactory to explain the viewing angle observations, whereas solid CO2 (and H2O ice) aerosol spheres, having a dominant particle radius range between 0.28 and 0.35 μ, could bring planetary and laboratory observations into compatibility. It is suggested, further, that solid CO2 aerosols could explain limb brightening in the blue spectral range. Various distributions of solid CO2 and H2O Mie particles with radii up to 0.35 μ show an opposition effect. However, the role of these aerosols in explaining the Mars opposition observations is very dependent on the optical properties of the underlying Mars surface material.
The theory of similarity for large-scale motions in planetary atmospheres
Authors: Golitsyn G. S.
Published: July 2016

A general similarity theory for dynamics of planetary atmospheres, which gives results consistent with those of more complex theories, is briefly outlined.
Cloud motions on Mars
Authors: Baum W. A. , Martin L. J.
Published: July 2016

A search of several thousand plates in the Lowell Observatory collection yielded 28 groups of plates on which the positions of well-defined transient bright spots (often assumed to be clouds) could be followed on a nearly daily basis. These groups of plates were from 15 different oppositions of Mars, starting from 1907 and ending with 1958. All but two of these spanned four nights or more, and the maximum interval covered was thirty nights. Whether they appeared to show motion or not, the successive positions and shapes of all apparently associated bright spots or clouds were plotted on Mercator projections with the use of a projection plate reader especially designed at the Planetary Research Center for planet image studies of this kind. Clouds near the limb were avoided.

The 28 groups of plates yielded 95 cloud histories. More than half appeared to be relatively stationary. Others showed definite motion well in excess of observational error but sometimes followed paths that partly doubled back upon themselves. The mean velocity for non-stationary clouds was found to be 5.6 km per hour, and the most commonly occurring direction of motion was eastward, particularly at high latitudes. The range of velocities found by this mapping procedure is nearly an order of magnitude smaller than values that have been estimated earlier by others from visual observations. These earlier observations are evidently in error, unless there exist clouds at high elevation, visible only on the limb, that can move much faster than those that were mapped from this photographic survey. More clouds were found in the northern hemisphere than in the southern, and there seemed to be an avoidance of the relatively darker areas of the Martian surface. Certain regions seem to be more favored than others. A few recurrences at identical positions suggest the existence of related topographic features.
The effective temperature of Jupiter'S equatorial belt during the 1965 apparition
Authors: Trafton L. M. , Wildey R.
Published: July 2016

Preliminary results from our study of Jupiter's equatorial limb darkening at 8–14 μ indicate that the effective temperature of the equatorial belt lay between 140 K and 150 K. We find these temperatures to be insensitive to the likely range of the He/H2 ratios. These results assume that Jupiter's only significant sources of extinction at these wavelengths are the pressure-induced absorption of H2 and He and the absorption of saturated NH3.
Observations of jupiter'S cloud structure near 8.5 μ
Authors: Westphal J. A.
Published: July 2016

Measurements of the distribution of thermal flux along polar and equatorial scans across Jupiter suggest that the increase in brightness temperature near 8.5 μ observed by Gillett et al. may be caused by flux coming from near the cloud tops. Other possible sources are discussed and observational tests suggested which should clarify the thermal structure of the upper atmosphere.
Techniques for Gamma Rays
Authors: Fichtel Carl E.
Published: July 2016

The detecting systems used in high energy astrophysics are generally more similar to particle detectors than to optical devices. The basic design of the gamma ray instrument depends on whether the energy range is below about 10 MeV and therefore in the region where the Compton effect predominates in the absorption of the gamma-rays, or above that energy where electron-positron pair production is most important. The most usual approach to the detector system in the lower of the two energy intervals is to use a scintillation counter in the center of the detector system to absorb the photons and permit a measure of their energy, and to surround it by another detector which is employed as an active anticoincidence shield to discriminate against charged particles. In the gamma-ray interval above about 10 MeV, the very low flux of gamma rays and the high particle background has directed the development of high energy gamma-ray telescopes towards complicated techniques and large detector arrays. As a result, several investigators have now turned to the spark chamber as the heart of a detector system. Generally, it is surrounded by an anticoincidence system and is triggered by a counter telescope.
Gamma-Ray Spectrometry of Galactic Sources in the Energy Range 0.2–3.0 MeV
Authors: Bui-Van A , Vedrenne G. , Mandrou P.
Published: July 2016

A low energy gamma-ray telescope (0.2–3 MeV) has been studied in our laboratory. It is made up of an active honeycomb collimator of Nai(T1), with a geometrical angular aperture of 1.5°, and of a detector composed of 73 Nai(T1) sticks (0.5 cm diam.–5 cm length) incorporated in a plastic gabarit used in anticoincidence.

The directivity of the telescope is obtained at low energy by the collimator, and at higher energy by the directivity which exists in the gamma-ray interaction through the Compton and photoelectric effects. The electrons emitted in these interactions which are not contained in the sticks of Nai(T1) are detected by the plastic anticoincidence scintillator. Only laboratory tests are presented here, for the study of the galactic gamma-rays, however, the system must subsequently be protected by a 4 cm thick anticoincidence well. In fact the detector directivity enables a great increase in the signal to noise ratio to be expected without greatly increasing the thickness of the shielding.

According to the results obtained the estimation of the minimum exposure time for the ‘Crab Nebula’ would be about 2h30m to have a signal at 1 MeV with 2σ of confidence above the background.
An Experiment to Measure the Direction and Energy Spectrum of Extraterrestrial Gamma Rays in the Energy Range 1–10 MeV from Balloon Altitudes
Authors: Dean A. J. , Bellomo A. , Coffaro P. , Fatta M. , Gerardi G. , Madonia F. , Russo A. , Scarsi L.
Published: July 2016

Problems of making a device for directional measurements of extraterrestrial gamma rays in the MeV-range are discussed – especially background counting rates. A detector system is described which is planned to be flown in a series of balloon experiments in order to provide a better understanding of the sources of background and their elimination.
Survey On New Techniques for X-Ray Astronomy
Authors: Giacconi Riccardo
Published: July 2016

The limitations imposed in X-ray astronomy observations by the use of sounding rockets with their inherent short time for observations and restricted payload capabilities will soon be surmounted when the new generation of X-ray experiments carried aloft by earth orbitting satellites is launched.

In the early 1970's several payloads included in the spacecrafts SASA, OSOH, SAS C, OSO 1, UK 5 and ANS will perform high sensitivity surveys of the entire celestial sphere. As a result of these experiments we expect to: increase the sensitivity of our observations by a factor of approximately 100; to improve the measurement of location on all known sources and on newly discovered ones to an accuracy of ½ to 6 arc min; to acquire more definite information on rapid time variations of the X-ray sources; to measure the polarization of the incoming X-ray radiation to several per cent for the strongest sources; and, finally, to determine for the strongest sources the existence of emission lines or absorption edges to the accuracy required to confirm or disprove present theories of source of emission processes and interstellar absorption.

Beyond these surveys a new generation of X-ray instrumentation utilizing focussing X-ray telescopes is in the planning stage. These instruments will yield a qualitative advance in the type of observations that can be performed. Location and structure of X-ray sources can be determined with these techniques to precisions of a few arc seconds to a limiting surface brightness of 10−14 erg/cm2 s (arc s2). Spectroscopy of the strongest sources can be carried out with energy resolutions λ/Δλ of 103 to 104. Polarization measurements can be carried out to a few per cent on the Crab and rapid varying events can be followed with a time resolution of 10−4 s.

A summary of the instrumentation will be given from the point of view of the developments and improvements which are being carried out to achieve the observational goals mentioned above.
A Bragg Spectrometer for Stellar X-Ray Astronomy
Authors: Kestenbaum H. , Angel J. R. P. , Novick R.
Published: July 2016

In the last year there have been several proportional counter observations of Sco X-1 which give an indication of an emission feature at around 7 keV (Holt et al., 1969; Acton et al., 1970). The emission lines of Fe+24 and Fe+25, which are very strong in radiation from solar flares of comparable plasma temperature, may be responsible for this feature. Two factors, poor energy resolution and the steeply varying continuum spectrum whose shape is not known in detail, make it impossible to obtain with proportional counters an unambiguous identification of emission features. For this reason we have constructed a Bragg crystal spectrometer to scan the spectrum of Sco X-1. The instrument, flown successfully aboard an Aerobee-170 rocket in April 1970 in conjunction with the Kitt Peak National Observatory, scanned the spectral range from 2.4–2.9 keV which includes the Lyman-α line of hydrogenic sulphur (2.62 keV). The spectrum obtained shows no feature at this energy. The sensitivity of the instrument may be judged from the upper limit (3σ) of 0.08 photon/cm2/s which we are able to place on the line intensity. This value can be compared with the flux of 0.55 photon/cm2/s predicted by Tucker (1967) for the S+15 line intensity from an isothermal, optically thin plasma at 5× 107K. If the line had had this theoretical intensity, we would have observed a 21-σ signal.
A Rocket-Borne X-Ray Spectrometer/Monochromator System for Mapping the Solar Corona
Authors: Acton L. W. , Catura R. C. , Culhane J. L. , Meyerott A. J.
Published: July 2016

A rocket payload is being prepared for the purpose of examining the spatial distribution of line emission from two important ions, Ovii and Neix, in the solar corona. The payload will contain the following integrated set of instruments.

(1) A pair of X-ray spectrometers utilizing KAP crystals of approximately 100 cm2 area.

(2) An optical aspect camera with a 1 Å bandpass H-α filter to measure the location of the field of view of the X-ray systems on the sun through out the rocket flight.

(3) A collimated proportional counter spectrometer operating in the 3 to 15 keV range.
Holographically Made Zone Plates for use in X-Ray-Telescopes
Authors: Rudolph D. , Schmahl G.
Published: July 2016

As it is well known one can obtain images of the Sun in the soft X-ray region and far UV region by use of zone plates. The main advantage of such imaging systems is the good resolution over a large field. There are however some disadvantages by using zone plates as imaging systems. These disadvantages are the wavelength dependence of the focal length and the zero order halo which diminishes the contrast of the image.
Results of Astronomical Studies in the Far UV Region
Authors: Kurt V. G.
Published: July 2016

In this survey I shall discuss only the results of studies which were obtained with instruments of moderate spectral and spatial resolution. The use of such instruments allows for the study of extremely weak fluxes in the UV region which are unaccessible to diffraction spectrometers of high resolution. In addition a broad field of view dispenses of strict attitude control system. Apparently, investigations of this kind are to be related to a study of sky background, including stellar and non-stellar components, and also to observations of planetary atmospheres from spacecraft in a near fly-by (Earth, Venus, Mars). Results obtained so far are impressive. It would be sufficient to say that due to UV observations the upper atmosphere of Mars has been studied for the moment with the same precision as that of Earth about 15 years ago.
Survey of New Solar Results
Authors: Tousey R.
Published: July 2016

Following a brief historical review, new observations of the sun in the wavelength range 3000 to 20 Å are surveyed for the period since about 1958. Vehicles employed have been sounding rockets, the OSO (Orbiting Solar Observatories), balloons for the window 2300–1900 Å and for λ > 2700 Å, and small orbiting observatories such as Solrad, for XUV solar monitoring. Advances have been made in spectral resolution, using echelle gratings and also Fabry-Pérot interferometers. Much progress has been made towards increased spatial resolution, to obtain spectra of specific solar features and to analyse the chromosphere and corona. Methods employed include spectrographs that are stigmatic, or that have a stabilized solar image projected onto the slit; slitless objective-type spectrographs; and observations during a total eclipse. Spectra have been obtained of a solar flare, showing its form and intensity in the emission lines between 171 and 630 Å. From OSO 4–6 many XUV spectroheliograms and spectra have been obtained over the range 300 to 1350 Å, with spatial resolution 35 × 35 arc sec in OSO 6. Photographic XUV spectroheliograms have provided solar images with spatial resolution as great as 3 arc sec in some cases. Although much effort has been spent to increase the accuracy of XUV intensity measurements, a great deal remains to be done before the requirements of solar physics theory are satisfied. Line identification, however, is proceeding well, although more laboratory spectroscopy is needed. Not included in the survey is the Bragg Spectrometer X-ray range below about 20 Å.
New Ultraviolet Solar Flux Measurements at 2000 Å Using a Balloon Borne Instrument
Authors: Ackerman M. , Frimout D. , Pastiels R.
Published: July 2016

A grating monochromator has been flown from Aire sur l'Adour (Landes) on May 10, 1968, April 19, 1969 and October 3, 1969. The instrumentation and the experimental procedure have been described previously (Ackerman et al., 1968) as well as the results of the first flight. For the two subsequent flights the wavelength marking was improved by increasing the number of the telemetered wavelength marking pulses. For the last flight the FM-FM analog telemetry system was replaced by a PCM telemetry system in such a way that the data analysis was completely made by means of a computer. Float altitudes were respectively 34, 38 and 37 km. From 1850 Å to 3000 Å up to 90 spectra per flight of the solar radiation penetrating into the atmosphere were telemetered to the ground. The solar zenith distance was ranging from 30° to 60°. The equivalent slit width was equal to 19 Å in the case of the first experiment and was equal to 14.6 Å for the two subsequent flights.
The Use of Echelle Gratings in Ultraviolet Space Astronomy
Authors: Boland B. C. , Burton W. M. , Jones B. B. , Reay N. K.
Published: July 2016

The echelle diffraction grating can be used to provide high spectral resolution in compact instrumentation which is very suitable for space astronomy applications. Spectrographs in which the high dispersion of the echelle is crossed with that of a concave grating have been flown in ‘Skylark’ sounding rockets to record the solar spectrum in the wavelength range 1200 Å–2200 Å, and further instrumentation is in preparation for observation of stellar spectra. Efficiency measurements have been made on some echelle replicas used in the instruments, and are correlated with surface conditions on the reflecting facets of the rulings. Results are also presented to demonstrate a spectral resolving power of λ/Δλ ≈ 105 over the wavelength range.
High Resolution Interference Spectroscopy Applied to Astronomical Investigations (2000 to 3000 Å)
Authors: Bates B.
Published: July 2016

For orbiting astronomical telescopes and for spectroscopic studies from rocket and balloon-borne platforms the great angular dispersion of the Fabry-Pérot interferometer should permit easier guidance tolerance for a given spectral resolving power with the added profit of the physical compactness of an etalon spectrometer or spectrograph. In addition, the superiority in luminosity and illumination of the interferometer permits shorter exposures and greater time resolution.
Instrumentation for High-Resolution Stellar UV-Spectrophotometry
Authors: De Jager C. , Hammerschlag A. , Werner W.
Published: July 2016

The paper describes the high-resolution stellar UV-spectrometer, experiment S 59 for ESRO TD-1 A satellite. The experiment utilizes the orbit and attitude control characteristics of the TD-1 A to obtain spectra of about 1 Å resolution from a few hundred bright early type stars with an instrument of moderate size. Attitude control of this large three-axis stabilized spacecraft is such that observing-instruments can search the sky along ecliptic meridians which precess by 360°/annum so that complete sky coverage is obtained in half a year.
A SEC Vidicon System for Satellite Applications
Authors: Brückner G. E.
Published: July 2016

This paper describes a small, low power SEC vidicon camera developed for recording images of the outer solar corona from an OSO satellite. The SEC vidicon has been selected for this application because of its capability to integrate and store low light level and low contrast images. The achieved signal to noise ratio will be discussed and compared with theoretical considerations. A new operational method to readout the tube very slowly will be described. The influence of a zero order data compression scheme on the quality of the coronal images will be discussed.
Review of Methods of Intensity Calibration in the Spectral Range 10–4000 Å
Authors: Mc Whirter R. W. P.
Published: July 2016

In this paper the bases of the various methods of intensity calibration in the vacuum ultraviolet will be examined. The remarks will be directed primarily at the problem of the measurement of spectral intensities from the sun from above the Earth's atmosphere. It is here that the requirements for intensity calibration are most demanding because of the greater sophistication and because the available range of the spectrum is more extensive. For the stars and other distant astronomical objects, hydrogen absorption limits the spectrum to wavelengths longer than about 900 Å although it transmits again in the soft X-ray region. Some reference will also be made to the problem of intensity calibration as it applies to laboratory spectroscopy, particularly where the object of the laboratory work is to measure astrophysically interesting rate coefficients or cross sections.
The Transition-Radiation as a Light-Source in the VUV
Authors: Böhm W. , Labs D.
Published: July 2016

Using the principle of the ‘transition-radiation’, it is possible to construct a new light-source for the VUV. This principle states that an electromagnetic radiation is emitted, when an electric charge penetrates the surface of a metallic target. The essential advantages of such a source are that it emits a continuous spectrum in the whole region from 1000 to 3000 Å and that this radiation is emitted directly in the vacuum.
Use of Synchrotron Radiation from An Electron Storage Ring as an Absolute Standard of Radiant Flux for Wavelengths from 1100 to 3000 Å
Authors: Fairchild Edward T.
Published: July 2016

The synchrotron radiation from the Wisconsin 240 MeV electron storage ring was used to calibrate the absolute sensitivity of photoelectric detectors to radiant flux at wavelengths between 1100 and 3000 Å. The spectrum from an electron in the storage ring beam was theoretically predicted and the number of electrons in the beam determined exactly by observing the discrete decreases in radiant flux as single electrons were removed from the stored beam. Interference filters of measured transmission were used to limit the flux to the particular wavelength bandpasses desired (200–300 Å). Photomultipliers for use as laboratory standards of radiant flux, and more recently flight photometers for stellar observation via rockets, were calibrated against this standard.
Nutation and the variation of latitude
Authors: Jeffreys Harold
Published: July 2016

A theoretical discussion by the author and R. O. Vicente uses geophysical estimates of the mechanical properties of the earth's shell and two extreme models for the core, chosen to make the mass and moment of inertia correct. The period found for the variation of latitude is in good agreement with observation. The 18.6-year nutation is in better agreement than has been found previously but is still not altogether satisfactory.
The fixing of the gaussian gravitational constant and the corresponding geocentric gravitational constant
Authors: Herrick Samuel
Published: July 2016

The author analyses the advantages of the use of the gaussian heliocentric gravitational constant. He proposes that a geocentric gravitational constant should be defined in an analogous way, that would present similar advantages.