Related papers: From Reference Frames to Relativistic Experiments:…
In this work, we study the classical phase space for the gravitational degrees of freedom along a null ray. We construct gauge-invariant observables localized on a null ray segment that commute with those localized on the complement; thus,…
A new observing mode for the Palomar Testbed Interferometer was developed in2002-2003 which enables differential astrometry at the level of 20 micro-arcseconds for binary systems with separations of several hundred milli-arcseconds (mas).…
Considering increasing requirements to the coordinates measurement precision by the end of XX century International Astronomical Union commenced implementation of the new astrometric system ICRF (International Celestial Reference Frame).…
We investigate the limits of ground-based astrometry with adaptive optics using the core of the Galactic globular cluster M5. Adaptive optics systems provide near diffraction-limit imaging with the world's largest telescopes. The…
High Definition Astrometry (0.1 - 1.0 micro-arcseconds) will open a new window into neighboring planetary systems. For the first time, the realm of temperate terrestrial worlds will be explored. This includes Earth Analogs, thereby allowing…
In this paper, we propose to use the scatter of celestial pole offset (CPO) series obtained from VLBI observations as a measure of the accuracy of the celestial reference frame (CRF) realizations. Several scatter indices (SIs) including…
The redshift of all cosmological sources drifts by a systematic velocity of order a few m/s over a century due to the deceleration of the Universe. The specific functional dependence of the predicted velocity shift on the source redshift…
In this paper, we overlay a continuum of analytical relations which essentially serve to compute the arc-length described by a celestial body in an elliptic orbit within a stipulated time interval. The formalism is based upon a…
In order to show the principle viability of a recently proposed relativistic positioning method based on the use of pulsed signals from sources at infinity, we present an application example reconstructing the world-line of an idealized…
We show that an interferometer moving at a relativistic speed relative to a point source of light offers a sensitive probe of acceleration. Such an accelerometer contains no moving parts, and is thus more robust than conventional…
We analyze the Michelson-Morley experiment in a reference frame moving with constant proper acceleration. Interestingly, we find an expected fringe shift which depends not only on the interferometer's rate of acceleration, but also on its…
Separate constituents of extended systems measure proper-times on different world-lines. Relating and comparing proper-time measurements along any two such world-lines requires that common simultaneity be possible, which in turn implies…
After an introduction on phenomena due to spin and mass-energy currents on clocks and photons, we review the 1995-2001 measurements of the gravitomagnetic field of Earth and Lense-Thirring effect obtained by analyzing the orbits of the two…
The most precise realization of inertial reference frame in astronomy is the catalogue of 212 defining extragalactic radiosources with coordinates obtained during VLBI observation runs in 1979-1995. IAU decided on the development of the…
The release of Gaia catalog is revolutionary to the astronomy of solar system objects. After some effects such as atmospheric refraction and CCD geometric distortion have been taken into account, the astrometric precision for ground-based…
Quantum reference frames have attracted renewed interest recently, as their exploration is relevant and instructive in many areas of quantum theory. Among the different types, position and time reference frames have captivated special…
We present an updated K band (24 GHz) celestial reference frame (CRF) constructed from 3.5 million Very Long Baseline Interferometry (VLBI) observations collected during 211 observing epochs between May 2002 and December 2025 using the Very…
Determining range, Doppler and astrometric observables is of crucial interest for modelling and analyzing space observations. We recall how these observables can be computed when the travel time of a light ray is known as a function of the…
Testing the effects predicted by the General Theory of Relativity, in its linearized weak field and slow motion approximation, in the Solar System is difficult because they are very small. Among them the post-Newtonian gravitomagnetic…
Nowadays, tens of satellites carry hyperspectral spectrometers. Such instruments allow decomposing the light that exits the atmosphere from its top into hundreds to thousands of contiguous spectral channels. By analysis of the light…