Speed Measurement in an Accomoving Reference System

Abstract

A method of direct measurement of the observer's velocity (peculiar velocity) relative to the accompanying reference system is proposed and investigated. To measure peculiar velocity, it is proposed to use the measurement of stellar light aberration. A comparison of the use of light aberration and the Doppler Effect for measuring velocity relative to relic radiation was made. When using the Doppler Effect, the total speed of the observer was measured - the Hubble speed and the radial component of the peculiar speed of the observer. As a result of the analysis of the components of the observer's velocity in the comoving reference frame, the Hubble and peculiar velocities of the observer, their essential features are formulated. The analysis of the shape of the wave fronts of the CMB radiation, the radiation of quasars, the radiation of stars and the radiation of ground sources is given. As a consequence of this analysis, the decisive influence of the shape of their wave fronts on the possibilities of measuring stellar aberration and the absence of such an effect when measuring velocity using the Doppler Effect are shown. Measurement of light aberration in an inertial system enables direct measurement of the observer's peculiar velocity in an comoving reference frame. Knowing the observer's peculiar velocity is important for increasing the accuracy of determining the Hubble velocity of especially objects of relatively small remoteness. The proposed structures of devices for measuring the peculiar velocity of an inertial reference system were investigated. Peculiar speed is determined by the measured light aberration without switching to another frame of reference. Their expected accuracy and reliability were evaluated. The practical use of the proposed structures is possible in astronomy and spacecraft.