Raghunatha Iyer Vakya Panchangam __link__ -

: The lunar day, used to determine festival dates and shraddham (ancestral rituals). Vaara : The day of the week.

While the Vakya system predates him by centuries, is the legendary figure who codified, popularized, and preserved the version most Tamils use today. Hailing from a family of traditional Ganitham (astronomy/mathematics) scholars, he lived during a time when British-educated pundits were beginning to dismiss traditional methods. Raghunatha Iyer Vakya Panchangam