| A corollary of this is that, before Hipparchus, astronomical tables based on Greek geometrical methods did not exist. |
| Geminus wrote a number of astronomy texts, including the elementary text Isagoge or Introduction to Astronomy based on the work of Hipparchus which we referred to above. |
| Ptolemy the astronomer was content with it, and according to him Hipparchus used no other. |
| Hipparchus was critical of the grid defined by Eratosthenes, saying reasonably enough that it was chosen arbitrarily. |
| The Romaka-Siddhanta was based on the tropical year of Hipparchus and on the Metonic cycle of 19 years. |
| Consequently, the length of the tropical year is now about ten seconds less than it was in the time of Hipparchus. |
