The total 2pN net shifts per orbit and the orbital precessions are calculated as the sum of two contributions: the direct ones due to the 2pN acceleration and the mixed, or indirect, ones caused by the 1pN instantaneous shifts during the orbital revolution. A comparison with other approaches existing in the literature is made.

The total 1pN gravitoelectric mass quadrupole orbital precessions of the Keplerian orbital elements are calculated in their full generality for an arbitrary orientation of the primary’s spin axis and a general orbital configuration of the test particle. Both the direct effects, due to the 1pN gravitoelectric mass quadrupole acceleration, and the mixed effects, due to the simultaneous action of the 1pN gravitoelectric mass monopole and Newtonian quadrupole accelerations, are calculated.

The orbital precessions of the Keplerian orbital elements induced by the 1pN gravitomagnetic spin octupole moment of a rigidly rotating oblate spheroid are calculated in their full generality for an arbitrary orientation of the primary’s spin axis and a general orbital configuration of the test particle.

The impact of the 1pN gravitoelectric mass monopole acceleration, both in the test particle and in the two-body system of finite, comparable masses cases, is calculated for different types of observation-related quantities (Keplerian orbital elements, anomalistic, draconitic, and sidereal orbital periods, two-body range and range rate, radial velocity curve and radial velocity semiamplitude of spectroscopic binaries, astrometric angles RA and dec., times of arrival of binary pulsars, characteristic timescales of transiting exoplanets). The results are applied to a test particle orbiting a primary, a Sun–Jupiter exoplanet system, and to a S star in Sgr A*.

The impact of the 1pN gravitomagnetic Lense–Thirring acceleration, generalized also to the case of two massive spinning bodies of comparable masses and angular momenta, is calculated for different types of observation-related quantities (Keplerian orbital elements, anomalistic, draconitic, and sidereal orbital periods, two-body range and range rate, radial velocity curve and radial velocity semiamplitude of spectroscopic binaries, astrometric angles RA and dec., times of arrival of binary pulsars, characteristic timescales of transiting exoplanets, and their sky-projected spin-orbit angle). The results are applied to a test particle orbiting a primary, a Sun–Jupiter exoplanet system, and an S star in Sgr A*.

The impact of the Newtonian quadrupolar acceleration, generalized also to the case of two bodies of comparable amsses and quadrpole moments, is calculated for is calculated for different types of observation-related quantities (Keplerian orbital elements, anomalistic, draconitic and sidereal orbital periods, two-body range and range rate, radial velocity curve and radial velocity semiamplitude of spectroscopic binaries, astrometric angles RA and dec., times of arrival of binary pulsars, characteristic timescales of transiting exoplanets and their sky-projected spin-orbit angle). The results are applied to a test particle orbiting a primary, a Sun-Jupiter exoplanet system, and to a S star in Sgr A*.