The corpus, every claim citable.

Pañcasiddhāntikā XIV (505 CE) teaches graphical methods: construct a degree-marked circle of 180 aṅgulis with auxiliary declination circles and strings, from which the ascensional difference for any latitude — and related rising-time quantities — are read directly off the figure. Thibaut's commentary describes the procedure as finding the result "without calculation, by the mere inspection of a kind of diagram": a worked analog-computing device inside a 6th-century astronomy curriculum.

The Panchasiddhantika: The Astronomical Work of Varaha Mihira · tr. G. Thibaut & Sudhakara Dvivedi, 1889