Light-Time Effect in the Eclipsing Binaries GO Cyg, GW Cep, AR Aur and V505 Sgr

Orbital period changes of the eclipsing binaries GO Cyg and GW Cep are explained by the light-time effect for the first time. New minima of the eclipsing binary AR Aur improve the predicted light-time orbit. The light-time orbit with the quadratic ephemeris of the binary matches the new observations of V505 Sgr better than the linear one. As the light-time effect fits in corresponding O − C diagrams of all four systems have been reaching extreme values, the observations of minima times in forthcoming years are highly desirable.     

The radius of the Sun at centimeter waves and the brightness distribution across the disk

We report observations of the solar radio radius at wavelengths between 1.2 and 11 cm performed with the Bonn 100 m-telescope. In combination with former measurements of the centre-to-limb variation of the solar brightness these observations are discussed in terms of atmospheric models. We consider the solar disk to be covered by arches at low latitudes, while at the poles coronal holes are located. The temperature dependence on height is taken from EUV-line intensities, hydrostatic equilibrium is adopted, spicules are assumed to be responsible for the relatively low brightening. The interpretation of our measurements demands certain values of the brightness temperature of spicules as a function of wavelength within a modest interval.     

On depth-dependence of photospheric oscillations

We report on results from photographic observations of photospheric oscillations as a function of depth. Using rms-values and power-spectra from shifts of entire line-profiles, we find qualitatively an increase of the velocity-amplitude with increasing height. We get more quantitative informations by comparing measured asymmetries of line-profiles with calculated ones derived from Voigt-functions containing a depth dependent velocity-field.We find the scale-height H ₀ of photospheric velocity oscillations to be 930±100 km. This result is to be compared with H ₀ = 1100±200 km obtained by Canfield (1976), who used velocity weighting functions of the line centres.Further, we show that a general observed line asymmetry of medium strong lines (c-shape) does not depend on the phase of oscillations.Mitt. aus dem Kiepenheuer-Institut Nr. 178.     

The design of the Central-Axis Reflector (ZAS)

The Central-Axis Reflector, the design principle which is presented below is a segmented-mirror telescope. The inventions relate mainly to the optical system and to the tracking apparatus.A large number of small individual mirror bodies, ground off-axis (hexagonal/polygonal) produce one primary mirror with closed circular aperture when joined together.The overall design of the tracking apperatus results directly —and thus without unnecessary adornment — from the two planes of to aminimum but which are required for tracking of the telescope.Paper presented at the Symposium on the JNLT and Related Engineering Developments, Tokyo, November 29–December 2, 1988.     

Die Ablenkung des Lichtes an der Sonne und die Änderung Seiner Geschwindigkeit und Wellenlänge

Zusammenfassung Die Ergebnisse der Radar-Echo-Messungen von I. I. Shapiro, welche auf eine Verringerung der Lichtgeschwindigkeit beim Vorübergang des Lichtes an der Sonne hinweisen, werden zusammen mit der Ablenkung des Lichtes und der Verschiebung seiner Spektrallinien wellentheoretisch erklärt. Es genügt hierzu die Annahme eines materiellen lichtwellentragenden Mediums mit einer Dichte unterhalb des empirischen Vakuums; das Medium muss dann radial zur Sonne eine geringe Inhomogenität besitzen, die in entsprechenden kleinen Zusatzgliedern in den Maxwellschen Gleichungen ihren Ausdruck findet.Auf protophysikalischer Grundlage aufbauend wird die Phasengleichung (22) der an der Sonne vorbeigehenden Lichtwellen unter einfachsten Annahmen abgeleitet und integriert; als Resultat ergeben sich die drei genannten Effekte in Übereinstimmung mit der Erfahrung (Gleichung (39), (44), (47)).

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Shapiro (1968) published the first results of radar-echo-observations on Venus and Mercury in the neighbourhood of upper conjunctions with the Sun; the observations indicate a decrease of the velocity of light passing the Sun. The theory of Soldner is disproved; and the general relativity is in accord with the observed facts. But not this theory alone. In this publication the deflection of light, decrease of the velocity of light, and displacement of spectral-lines are explained with the aid of a wavetheory. Hereby the assumption of a material medium carrying light-waves is sufficient, the density of which is below that of the empirical vacuum; hence, the medium must have a small inhomogeneityh radial to the Sun, and the Maxwell equations contain small additional terms (Equation (3)). They lead to the field equations (4) and (5). The protophysical fundamentals of the wave-theory (6), (8), (9), (10a) lead to the Equations (12) of wave-phase. If we assume that the behaviour of the light passing the Sun is independent (in first approximation) from the wave-form (F), the Equation (22) of wave-phase, is deduced for simple-periodic waves of light. Figure 1 outlines the slope and deflection of the ray of light by the Sun. Section 5 contains the solution of (22); and Section 6 the results. The constant of inhomogeneity =1/210^–5 (of the radius of the Sun) produces a deflection (39) of light passing the Sun. The length of waves of the light approaching the Sun is decreased to a minimum and is increasing with increasing distance from the Sun until the former value ((43) and (44)). The velocity of light approaching the Sun is decreased to a minimum and increases with increasing distance from the Sun to its former value ((46) and (47)).

     

North-south asymmetries in the green corona brightness between 1947 and 1976

The north-south asymmetry has been studied using the green emission corona brightness in the period of 1947–1976. (N - S)/(N + S) values are constructed with the 5-deg opposite coronal belts brightnesses between ± 5 and ± 60 deg. Power spectra analyses were performed to study periodicities of these (N - S)/(N + S) values. Two noticeable periodicities (14.5 and 5 yr) have been found.     

Separation of deterministic signals using independent component analysis (ICA)

Independent Component Analysis (ICA) represents a higher-order statistical technique that is often used to separate mixtures of stochastic random signals into statistically independent sources. Its benefit is that it only relies on the information contained in the observations, i.e. no parametric a-priori models are prescribed to extract the source signals. The mathematical foundation of ICA, however, is rooted in the theory of random signals. This has led to questions whether the application of ICA to deterministic signals can be justified at all? In this context, the possibility of using ICA to separate deterministic signals such as complex sinusoidal cycles has been subjected to previous studies. In many geophysical and geodetic applications, however, understanding long-term trend in the presence of periodical components of an observed phenomenon is desirable. In this study, therefore, we extend the previous studies with mathematically proving that the ICA algorithm with diagonalizing the 4th order cumulant tensor, through the rotation of experimental orthogonal functions, will indeed perfectly separate an unknown mixture of trend and sinusoidal signals in the data, provided that the length of the data set is infinite. In other words, we justify the application of ICA to those deterministic signals that are most relevant in geodetic and geophysical applications.