Daily calendar: method & sources

The date and clock use the calendar location’s configured time zone, rather than the visitor’s device location.

Chennai sunrise and sunset use 13.0827° N, 80.2707° E and India Standard Time. These are approximate NOAA solar-equation calculations using a 90.833° solar zenith. Atmosphere, elevation and local horizons can affect observed times.

Rahu Kalam, Yamagandam and Gulikai use traditional weekday eighths of the sunrise-to-sunset interval at the configured calendar location. Chennai solar times are shown separately and clearly labelled.

Tamil month starts follow the Government of India Positional Astronomy Centre / IMD regional-calendar table for 2026–27. The built-in table is bounded to 14 April 2026–15 March 2027. Outside that range the owner must enter a verified Tamil date; month-start dates are never repeated mechanically in another year.

Nalla Neram, Nakshatra, Tithi, Dina Shuddhi, Amrita Kadigai and Tamil yoga are date- and location-specific owner entries. Amirtha, Siddha and Marana are Tamil Amirthathi yogas, distinct from the 27 astronomical nitya yogas. Entries can describe transitions during the day; Amrita periods can explicitly end the next day. Missing entries stay pending and yesterday’s values are never reused.

NRI visitors should consult timings for their own location.

• NOAA · Solar equations
• IMD / Positional Astronomy Centre · Regional calendars 2026–27
• Drik Panchang · Chennai Tamil panchang