ABSTRACT
For the determination of elements of the elliptic orbit it is necessary to have complete observations of the celestial body. The idea of splitting the problem of determination of the elliptical orbit into two stages is preserved: first, determination of the geocentric distances of the celestial body; second, determination of orbital elements themselves. The first method for determination of the semimajor axis of an elliptic orbit was proposed by Gauss in 1801. More practical and more convenient method for the determination of the semimajor axis was proposed by Moulton in 1901, exactly a hundred years after Gauss. Everything seems all right, and no additional equation like the Gauss equation has to be built up for parabolic orbit. The heliocentric distance also exists in the case of a parabolic orbit, again within the basic equations.
