About

A panchangam that shows its reasoning: computed at your own town's sunrise, with every rule traced to the text it comes from.

A panchangam has two halves. One is astronomy — where the Sun and Moon actually are, at a particular place, at a particular moment. The other is the body of rules a tradition uses for reading that sky into a calendar.

Most almanacs give you the answer. We give you the answer and the reasoning, because the reasoning is what lets you tell whether an answer applies to your household.

The astronomy

Positions are computed with the Swiss Ephemeris under the Lahiri ayanamsha, for the sunrise of the town you ask for rather than a regional average. Two towns a hundred kilometres apart do not share a horizon, and on the days that matters, it matters a great deal.

The rules

Every observance rule here is traced to a classical text — the Dharmasindhu for the vrata decisions, the Calendar Reform Committee's report for the South Indian criteria. We name the text and the passage on the page that uses it.

Where traditions differ

They differ often, and legitimately. Smarta and Vaishnava households test ekadashi at different moments and keep the fast on different days. States observe Janmashtami on different dates because they apply different tests to the same ashtami.

Where that happens we set out both readings and name the rule behind each, so you can follow the one your family keeps.