The extant data on latitudes ascribed to Eratosthenes and Hipparchus have been
compiled and tested for consistency using adjustment theory. For the detected
inconsistencies new explanations are given concerning the origin of the data. Several
inconsistent data can be ascribed to Strabo. Differences in Hipparchus’ data can
often be explained by the different types and precision of the data. Gross errors in
Eratosthenes’ data are explained by their origin in lengths of sea routes. From
Eratosthenes’ data concerning Thule a numerical value for Eratosthenes’ obliquity of
the ecliptic is deduced.
Keywords
Eratosthenes, Hipparchus, Strabo, latitudes, obliquity of
the ecliptic, length of the longest day, prime meridian,
Thule
