About IndiaTime
Sources and Calculation Methods
Find the basis of IndiaTime’s clocks, conversions, daylight calculations, calendar readings and institutional schedules.
Clocks and dated timezone conversion
The clock requests a reference from the same-origin /api/time endpoint, estimates request delay and advances the reading with a monotonic browser timer. A recent reference is refreshed periodically; the clock labels device-time fallback when a reference cannot be obtained.
Named-city conversions use the browser’s timezone rules for the selected date. Reverse conversion checks whether a local clock time occurs once, twice or is skipped at a seasonal transition. IANA’s timezone database documents the regional rules, while CSIR-NPL maintains India’s official time reference.
Sun, Moon and traditional timing windows
City-centre coordinates and SunCalc 1.9.0 supply sunrise, sunset and approximate lunar illumination. Observed horizons and elevation can change what is seen from a particular site. The city and civil date stay beside each result.
| Reading | Calculation used |
|---|---|
| Rahu Kaal and Gulika | Local daylight divided into eight intervals, using the stated weekday position. |
| Brahma window | 96 to 48 ordinary minutes before the calculated sunrise. |
| Daytime midpoint / Abhijit window | One fifteenth of daylight centred on its midpoint. |
| Moon phase transitions | SunCalc phase crossings, rounded to the nearest IST hour. |
| Sunrise-based Vedic illustration | The interval between successive Ujjain sunrises scaled to the displayed 30-hour cycle. |
The Vedic-clock page identifies the Vikramaditya Research Institute reference and explains the illustration’s dial. A phase percentage, a sunrise tithi and a festival’s observance rule are separate readings.
Modern Calendar / Gregorian and regional readings
National Saka conversion uses the solar month lengths and March new-year rule described by the Government of India national calendar reference. Its leap-year and year-boundary examples are tested separately.
The Hindu tool calculates sunrise tithis using Astronomy Engine 2.1.19, with North Indian Purnimanta, Gujarati Amanta and Deccan Amanta readings. The published tables cover eight cities during 2026–2027 and retain extra-month and near-sunrise boundary information. Selected boundaries are compared with linked daily almanacs.
The Hijri comparison uses the Islamic civil tabular calendar and a displayed day adjustment. Expected festival dates come from their own records. A calculated conversion does not change a community announcement.
Government offices, banks and markets
Each institutional record names the body it applies to. State-government office dates come from the linked annual order. RBI holiday matrices supply centre-specific bank dates; Sundays and second/fourth Saturdays are generated as a separate weekly rule. Central-office dates keep their DoPT scope.
Exchange holidays and special sessions use the named exchange’s segment-specific notices. RBI, FOMC and MoSPI economic dates retain the published date range, timestamp or tentative status. A closure at one institution does not close every office or service.
The record catalogue, state-order records and feed manifest expose the dates and sources used by the Calendar tools.
Calendar downloads and revisions
All-day entries use civil dates with an exclusive following-day end. Timed meetings and economic releases retain their precise instant for conversion by a calendar app. Subscription feeds have stable addresses and event IDs; the app controls when it refreshes them.
A one-time download is a snapshot. Expected dates retain tentative status. Government, bank, exchange and festival records keep their own scope in the export. Monthly Hindu, Saka and Hijri downloads follow the convention or adjustment selected in the tool.
Heritage, maps and product research
Heritage claims use institutional references such as UNESCO, district observatory accounts and identified texts. Mathematical diagrams and worked examples explain the cited principles. Product comparisons use manufacturer documentation and identify desk research explicitly.
The world map uses Natural Earth public-domain geography with the processing record in the map source file. Its daylight shading is illustrative; city clocks supply the civil-time comparison.
Review and corrections
Review dates identify an actual content or source check. A later institutional amendment is recorded against the affected data; missing coverage is not filled by inventing a schedule. Send a reproducible correction through Admin’s contact details.
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