Sources

These are the texts and astronomical tools behind the dates and timings on this site.

The Pradosham and Navratri articles cite the Dharmasindhu passages behind their rules. The astronomy pages show how the daily timings are calculated.

Observance rules

Dharmasindhu, by Kāśīnātha Upādhyāya, is a source for the vrata and festival rules explained here. You can read the scanned copy in the Karnataka Samskrit University collection. The method pages name the relevant passages and leaves.

We use the Report of the Calendar Reform Committee (1955) for solar month boundaries and for its criteria on observance dates.

Sewell and Dikshit, The Indian Calendar and Swamikannu Pillai, Indian Chronology are cited where their calendar explanations are used.

Astronomical and regional methods

The weekday order of Yamagandam and Gulikai follows Kalaprakashika.

Published calendars

Our dates are compared with Drik Panchang's Delhi calendar and with the Tamil calendars of prokerala and Oneindia.

Computed positions

The site calculates astronomical positions with the Swiss Ephemeris and uses its standard Lahiri ayanamsha setting for sidereal positions.