Columbia subject headings:
Astronomical clocks.
Astronomy, Medieval--Instruments.
Planetary theory.
Ptolemy, active 2nd century.
Harvard subject headings:
Astronomical clocks
Astronomy, Medieval--Instruments.
Planetary theory.
Ptolemy, active 2nd century.
Princeton subject headings:
Astronomical clocks.
Astronomy, Medieval--Instruments.
Planetary theory.
Ptolemy, active 2nd century.