Einfluß verbesserter Deklinationswerte auf die PZT-Breiten-bestimmungen in Potsdam (Mitteilungen des Zentralinstituts für Physik der Erde Nr. 1027)

The results of latitutde determinations with the PZT at Potsdam observatory in the years 1972–78 were used to improve the declinations of the observed stars. The latitude determinations were re-reduced with the calculated corrections of declinations in the system of the new catalog. The obtained results show a substantially better agreement and a higher stability with respect to the BIH system than the results in the system of the hitherto used star catalog.     

Relationen zwischen Störungen des lokalen Temperaturfeldes und den geodätisch-astronomischen Beobachtungsresultaten am Astrolab DANJON (Mitteilungen des Zentralinstituts für Physik der Erde,Nr. 955)

The long-term series of geodetic-astronomical observations are an important data basis for geodynamic investigations, but the microclimatic influence on their results is an uncontested fact too. The local topography brings about thermal anomalies and thus it is the cause of the inclination of isopycenics and refraction disturbances. The measuring equipment is described for the temperature registration near the astrolabe DANJON at the observatory Potsdam. It is reported on quality and treatment of measuring dates and on design of the graphic temperature-model. In the 6-metre plane, horizontal temperature gradients were determined in the azimuth of all stars observed. They yield direct information about the thermally caused inclination of the layers of equal density in the differentially small region which is passed by the beam of light coming from the star. The correlation between these gradients and the geodetic-astronomical observations are detected. The corrections produced on the basis of the regression analysis are computed for significant correlations (about 30%). An improvement and extension of the temperature recorder is discussed with a view to a higher effect of this method.     

Astronomische Längen-und Breitendifferenzen der Basisobservatorien Irkutsk,Potsdam und Simeiz (Mitteilungen des Zentralinstituts für Physik der Erde,Nr. 1180)

In 1980/1981 astronomical observations using a carried DANJON -astrolabe were made at Irkutsk, Potsdam and Simeiz stations in order to determine the longitude and latidute differences. — It is informed about the observations made and the analysis of the results obtained. The formulas required for the astronomical longitude and latitude determination are indicated. Subsequent calculation of the weighted mean serves to stepwise condence the values and, at the same time, to examine them for systematic groupe differences and personal errors. Finally the longitude and latitude differences are derived taking into account the observers' personal equations. Their accuracies range from ±0.0020 s to ±0.0028 s and from ±0.013”︁ to ±0.017”︁, respectively. Russian text ingnor     

BIANCHI-I-Kosmen der BRANS-DICKE-Theorie für das Vakuum

The field equations of the BRANS -DICKE theory are solved for a vacuum with the aid of a space-time metric of BIANCHI -I-type. Two solutions are found. One of them corresponds to a generalization of the flat de SITTER -universe. On the other side we have obtained the KASNER -like solution on the basis of original the version of BRANS -DICKE theory.     

The outer core rotation about an inclined axis from geomagnetic secular variations (Mitteilungen des Zentralinstituts für Physik der Erde,Nr. 1832)

Non-axisymmetric motions of the outer core of the Earth are important for the dynamo problem and the excitation of the decade variations of the polar motion. The components of the vector of a rigid rotation of the outer core about an inclined axis were estimated by a first-order approximation of the frozen- field theory of the geomagnetic secular variation from 1903.5 to 1975.5. The trends and quasi-periodic constituents of these quantities were computed. It was shown that the position and time behaviour of the rotational pole of the outer core differ considerably from the well-know co-ordinates of the dipole axis. Some periods of the equatorial components of the rotational vector are comparable with those of the axial component previously derived for a pure axial rotation. Additionally, the time behaviour of the pole path shows events like the well-known Markowitz wobble but naturally with other extent. These and other results suggested that the investigations are worth to be continued in future by some physical interpretations.     

The periodic variations of the core drift rate: global and zonal motions (Mitteilung des Zentralinstituts für Physik der Erde,Nr. 1746)

Toroidal zonal motions at the top of the Earth's core were computed from the observed secular variation and investigated with regard to their time dependence. Previously derived results for a pure westward drifting core could be re-examined. Additionally, the well-known 66.7 years period was found to be an oscillation of the zonal velocity field of third degree. With respect to periodic constituents, the total magnetic core-mantle coupling torque according to the zonal motions is comparable with that derived for a pure westward drifting core. Some differences in period lengthes and amplitudes do not remove previously stated differences between the spectra of the magnetic and mechanical torques on principle.     

The New Programme of Observations with the DANJON Astrolabe of Potsdam Geodetic-Astronomical Observatory (Mitteilungen des Zentralinstituts für Physik der Erde,Nr. 821)

The old programme of observations (cf. Beobachtungsergebnisse 1964 and Astronomische Zeit- und Breitenbestimmungen 1965, 1) was modified. The conditions described in Instruction (1956) were used again. As previously (cf. Beobachtungsergebnisse 1964), the stars were selected in respect of the derivation of corrections to the co-ordinates of the stars. The new programme, which has been in use since September of 1978, can be used up to the year 2000.     

UBV-Beobachtungen und Periodenbestimmung für den Delta Scuti Stern HD 177392

UBV observations of the Delta Scuti type star HD 177392 were carried out in 7 neights. The three periods o⁴1215, o⁴11091, and o⁴109414 were found. These periods can not be explaine by radial pulsation.     

Alfred Wegener und die Physik der Hochatmosphäre

Extracts from the papers of Alfred Wegener relating to noctilucent clouds, aurora (including the so-calling geocoronium) and other upper atmospheric phenomena are presented here so as to give an idea of his contribution to this subject made during the years of 1900–1930.     

Beobachtungsergebnisse der Berliner Arbeitsgemeinschaft für Veränderliche Sterne e.V. (BAV)

In this 11th compilation of BAV results of observations are given from the years 1973 till 1975 for 217 observed minima of 56 eclipsing binaries, 173 maxima of 25 RR Lyrae stars, 624 results of 89 Mira stars, 182 results of 47 RV Tauri stars and irregular variables, 52 results of 27 eruptive variable stars and 12 maxima of four δ Cephei stars.     

Beobachtungsergebnisse der Berliner Arbeitsgemeinschaft für veränderliche Sterne e. V. (BAV)

In this 9th compilation of BAV results of observations are given from the years 1969 up to 1971 for 208 observed minima of 46 eclipsing binaries, 72 maxima of 22 RR Lyrae- and δ-Cephei-stars, 232 results of 66 Mira stars, 72 results of 12 RV Tauri-stars and 22 results of 3 irregular variables and U Geminorum-stars.     

Beobachtungsergebnisse der Berliner Arbeitsgemeinschaft für veränderliche Sterne e. V. (BAV)

In this 8th compilation, the following results of observations are given: 207 observed minima of 56 eclipsing binaries, 100 maxima of 21 RR Lyrae- and δ Cephei-stars, 82 results of 32 Mira stars and long period variables, and 47 results of 9 RV Tauri stars, semiregular, and irregular variables, from the years 1966 up to 1968.     

Beobachtungsergebnisse der Berliner Arbeitsgemeinschaft für veränderliche Sterne e.V. (BAV)

In this 10th compilation of BAV results of observations are given from the year 1972 and some from the year 1969 for 187 observed minima of 50 eclipsing binaries, 84 maxima of 18 RR Lyrae- and δ Cephei-stars, 123 results of 55 Mira stars and 85 results of 15 RV Tauri-stars and irregular variables.     

Zur dynamischen Äquivalenz der post-NEWTONSCHEN Näherung für die Planetentheorie in der allgemeinen Relativitätstheorie und in der trägheitsfreien Mechanik mit RIEMANNSchem Gravitationspotential

Proof of the dynamical equivalence of the post-NEWTONian approximations for the LAGRANGAIN representations of planetary motions according to GRT and according to our “RIEMANNian dynamics with MACH EINSTEIN doctrine”. Finally, we discuss the equivalence problem for general post-NEWTONian LAGRANGians of the one-body Problem in celestical mechanics.     

Die multidimensionale Ungleichung von BERNSTEIN und die Abschätzung der Ableitungen des Gravitationspotentials

In different problems of celestial mechanics it is often necessary to estimate the effect of the truncated higher harmonics of the gravity potential on the motion of a test particle. As a rule the magnitude of this effect is strictly connected with the gravitational acceleration, i.e. partials of the potential. But the mathematical theory of attraction gives the estimations for the potential itself. However, as far as the general term of development (spherical harmonic) possesses a definite reserve of the smoothness, we have succeeded in passing from potential estimations to its partials estimations. The mathematical method based on a multidimensional generalization (obtained here) of an inequality by BERNSTEIN is used. By the way several inequalities connecting different norms of spherical harmonics are proved.     

Die Bewegung in der Nähe der Dreieckspunkte des elliptischen eingeschränkten Dreikörperproblems

Zusammenfassung Die Gleichungen der Bewegung des kleinen Körpers in der Nähe der DreieckspunkteL ₄,L ₅ des elliptischen eingeschränkten Dreikörperproblems werden mit Hilfe eíner eínfachen Transformation explizit in zwei unabhängige Komponenten aufgespalten, welche den bekannten Bewegungsfamiliedd unde des Kreisfalles entsprechen. Aufgrund dieser Zerlegung wird für die Bewegung im elliptischen Fall eine erste Stabilitätsgrenze berechnet, welche die Ergebnisse anderer Autoren präzisiert.Die Arbeit wurde vom Bundesministerium für Bildung und Wissenschaft in Bonn gefördert. Der Verfasser dankt dem Ministerium für die erwiesene Unterstützung.

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A simple transformation is used to divide explicitly the equations of motion of an infinitesimal body in the neighborhood of the triangular pointsL ₄,L ₅ in the elliptic restricted Three-Bony-Problem into two independent components corresponding to the well-known families of motiond ande in the circular case. This separation immediately gives a first stability constraint for the elliptic case which is more exact than the results prior given by other authors.The work presented in this paper was supp orted by the Federal Ministry of Scientific Research in Bonn, Germany. The author gratefully acknowledges the sponsorship granted by the Ministry.

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Herrn Prof. Dr. L. Merz, TH München, zum 65. Geburtstag gewidmet     

Die Aufspaltung der Variationsgleichungen des Elliptischen Eingeschränkten Dreikörperproblems

Inhalt Die in einer früheren Arbeit vorgelegte Aufspaltung der Variationsgleichungen 4. Ordnung für die Dreieckspunkte des elliptischen eingeschränkten Dreikörperproblems in zwei Komponenten 2. Ordnung wird auf beliebige Variationsgleichungen des Problems ausgedehnt.

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The separation of the 4th order variational equations into two 2nd order components in the elliptic problem of three bodies presented in a previous paper for the triangular points is extended to any variational equations of the problem.

     

Die Bewegung in der Nähe der Dreieckspunkte des elliptischen eingeschränkten Dreikörperproblems II

The explicit separation of the motion close to the equilateral points of the Elliptic Restricted Problem (ERP) into two 2nd order components presented in a previous paper is used for stability investigations of this motion. By means of simple approximate solutions for the components there are computed analytical curves of constant basic frequency and of stability boundaries with high accuracy in the plane of parametersg ande. The results of other authors are corrected or made more precise.     

On Measuring the Dynamical Age of Clusters of Galaxies (Mitteilungen der Universitätssternwarte zu Jena Nr. 139) Universitätssternwarte and Zentralinstitut für Astrophysik der Akademie der Wissenschaften der DDR With 4 Figures

The method for measuring the dynamical age of n-body systems proposed by S. von HOERNER (1976) is applied to clusters of galaxies. The modulus of evolution W characterizing quantitatively the dynamical state of the cluster was determined for several objects. It turns out that the Virgo cluster is one of the dynamically youngest clusters.