Tuesday 21 December

How it was decided

1. 01

   Aṅga

   Pūrṇimā runs from 18:15 on Mon 20 Dec to 20:52 on Tue 21 Dec.

   1915-12-20T10:15:21Z → 1915-12-21T12:51:57Z

2. 02

   Kāla

   Pradoṣa is 2 muhūrtas after sunset: 16:58–18:55 on the 20th, 16:59–18:55 on the 21st.

   pradosha: night-muhurta-1-2 · sunrise and sunset: upper limb, 31′ + 16′

3. 03

   Rule

   Pūrṇimā must be present during pradoṣa. It covers 39 of 117 minutes on the 20th and 117 of 117 on the 21st.

   Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 104

4. 04

   Tie-break

   Both evenings qualify and the rule marks neither. The one covered longer is ruled, as a boundary.

   priority: unstated → greater-coverage · margin 2370 s

5. 05

   Ruling

   Dattātreyotpatti, Baoding, 1915: Tuesday 21 December.

   confidence: boundary (tie-break-unstated)

Say it like this

In Baoding, Dattātreyotpatti (Datta Jayanti) 1915 falls on Tuesday 21 December. Pūrṇimā runs from 18:15 on Mon 20 Dec to 20:52 on Tue 21 Dec and covers all of pradoṣa that evening. It also reaches the previous evening for 39 minutes; the rule does not say which to take, and the one covered longer is ruled: treat the date as contested.

Copy with citation

Who says what

Institutional rulings are recorded with a source address, and are never edited to agree.