Among the topics are relativity for astronomy, celestial mechanics, and metrology; terrestrial coordinates
and the rotation of the Earth; orbital ephemerides of the Sun, Moon, and planets; eclipses of the Sun and Moon; and calendars.
The device manifested the possibility to register gravitational perturbations of non-seismic kind from the internal processed in the terrestrial globe, and locate the terrestrial coordinates
of the sources of the perturbations.
However, sometimes you need to know your terrestrial coordinates
to a finer degree.