Assertion: precession | /r/AtLocation | almagest
Facets:
Source sentences:
text: All that is known of Hipparchus's study of what we now call the precession is contained in [Ptolemy's] Almagest 3.1 and 7.1-3, and it is evident from Ptolemy's account that it was highly technical, highly tentative, and did not necessarily indicate anything like a motion of the entire sphere of the fixed stars with respect to the equinoxes.