Dangaus kūnų poveikio vertikelei įvertinimas

Abstract

Influence of the Moon and the Sun on the vertical on the Earth's surface was evaluated. Formula for determination of vertical deflection is given. Possible deflections of the vertical on Lithuanian territory and changes of point heights related to it were evaluated. Research was done by using lately accepted values of astronomic and geodetic constants. Range of the vertical changes for the Earth from -0.015’’ to 0.015’’ for the Moon and from -0.006’’ to 0.006’’ for the Sun. Possible changes of height differences from -0.18 mm to 0.18 mm for the Moon and from -0.07 mm to 0.07 mm for the Sun, when the distance between the points is 2.5 km. It was determined that in most precise geodetic activities deflection of the vertical caused by the Moon should be computed by taking into account two terms of tide potential and the elliptic orbits of the Moon and the Earth. Fluctuation of geocentric ranges and gravity values for points on Lithuanian territory is not essential for changes of celestial bodies influence on the vertical, therefore mean values of mentioned parameters could be used for the country's territory. Constant observations of gravity field must be performed for determining of precise vertical deflection.