Tables are classified according to different types. These different types correspond to the specific steps in astronomical computationas organised by historical actors. In modern terms, these types correspond to distinct classes of mathematical functions which express a portion of an underlying astronomical theory.

Quickly changing its position with respect to the Sun, it comes back against the same star in a cycle of about 88 days, appearing sometimes east and sometimes west but Mercury is difficult to observe because of its proximity to the Sun.

Glossary