Relativistic Reduction of Astrometric Measurements

Author(s):  
V. A. Brumberg
1990 ◽  
Vol 141 ◽  
pp. 229-240
Author(s):  
V. A. Brumberg ◽  
S. A. Klioner ◽  
S. M. Kopejkin

The framework of general relativity theory (GRT) is applied to the problem of reduction of high precision astrometric observations of the order of one microarcsecond. The equations of geometric optics for the non-stationary gravitational field of the Solar system have been deduced. Integration of the equations of geometric optics results in the isotropic geodesic line connecting the source of emission (a star, a quasar) and an observer. This permits to calculate the effects of relativistic aberration of light due to monopole and quadrupole components of the gravitational field of the Sun and the planets taking into account their motions and rotation. Transformations between the reference systems are used to calculate the light aberration occurring when passing from the satellite system to the geocentric system and from the geocentric system to the baryecntric system. The baryecntric components of the observed position vector reduced to the flat space-time are corrected, if necessary, for parallax and proper motion of a celestial object using the classical techniques of Euclidean geometry.


An expression for the non-additive, three-body interaction energy of three neutral atoms is deduced, by the methods of quantum electrodynamics. Non-relativistic reduction and dipole approximation result in an expression which for interatomic separations R small compared to the wavelengths of typical atomic transitions reduces to the triple-dipole energy varying as R –9 (Axilrod & Teller), whereas at distances large compared with these wavelengths, the three-body interaction energy becomes proportional to R –10 , owing to the influence of retardation.


2020 ◽  
Vol 954 ◽  
pp. 114994
Author(s):  
Rabin Banerjee ◽  
Debashis Chatterjee

1986 ◽  
Vol 109 ◽  
pp. 19-42 ◽  
Author(s):  
V. A. Brumberg

The nonuniqueness of the quasi-Galilean coordinates of general relativity leads to the emergence of unmeasurable coordinate-dependent quantities in astronomical practice. One may offer three possible ways to overcome the related difficulties: 1.developing theoretical conclusions only in terms of measurable quantities2.using arbitrary coordinates and developing an unambiguous procedure for comparing measurable and calculated quantities3.agreement to utilize one and only one coordinate system.In this paper we prefer the second way. After formulating the heliocentric planetary and geocentric satellite equations of motion, the general technique for relativistic reduction in astrometry and geodynamics is developed. Specific algorithms for the reduction of absolute and relative measurements are derived for the one- and the two- body problem. For illustration, the relativistic reduction of stellar parallaxes, Doppler satellite observations, navigation measurements with the aid of satellites and radiointerferometric measurements are presented in detail.


2000 ◽  
Vol 180 ◽  
pp. 308-313 ◽  
Author(s):  
S. Klioner

AbstractIt is argued that the relativistic definitions of parallax, proper motion and radial velocity consistent with an accuracy of 1 μas should be considered only within a well-defined algorithm of relativistic reduction of observational data. Such an algorithm is formulated and the corresponding definitions of astrometric parameters are discussed.


1980 ◽  
Vol 56 ◽  
pp. 283-294
Author(s):  
V. A. Brumberg

AbstractWith the accuracy of modern observations the relativistic treatment of the basic astronomical reference frames only requires the consideration of comparatively simple types of metrics such as heliocentric Schwarzschild metric, geocentric Schwarzschild metric and metric of the Earth-Sun system. Dynamical (related to the motion of the bodies) and kinematical (related to the light propagation) characteristics of these metrics enable one to perform the accurate relativistic reduction of astronomical measurements. In this reduction, the choice of specific quasi-Galilean coordinates may remain arbitrary. This paper presents expressions for the main relativistic terms in coordinates of the principal planets and Moon using the PPN formalism parameters β, γ and coordinate parameter α. General formulae for the reduction of radar, radio-interferometric and astrometric observations of planets and for the interpretation of lunar laser ranging are given. For estimating the actual magnitude of relativistic effects, the ephemeris data should be expressed in terms of physically measurable quantities.


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