Ruling · Dattātreyotpatti (Datta Jayanti) · 1971

Wednesday 1 December

Boundaryin Baoding, under the Rashtriya Panchang method. Pūrṇimā reaches pradoṣa on neither day and the rule does not say what then. Say “contested”.

Decide it for

BaodingDelhiKolkataSingaporeSydneyJersey City

38°52′ N 115°28′ E · Asia/Shanghai · GeoNames 1816971

The two evenings

One ghaṭī is 24 minutes. Pradoṣa is 2 muhūrtas after sunset.

Evening of Wednesday 1 December

Taken. Pūrṇimā reaches neither evening; this is the day it falls on.

16:57 sunsetpradoṣa ends 18:51
Pūrṇimā begins 18:54:27
16:3316:5717:2117:4518:0918:3318:5719:21

0 of 115 minutes covered

Evening of Thursday 2 December

Pūrṇimā is absent from pradoṣa. Not taken.

16:56 sunsetpradoṣa ends 18:51
16:3216:5617:2017:4418:0818:3218:5619:20

0 of 115 minutes covered

Pūrṇimā presentPradoṣa, the window the rule readsThe instant the tithi begins or ends

How it was decided

  1. 01

    Aṅga

    Pūrṇimā runs from 18:54 on Wed 1 Dec to 15:48 on Thu 2 Dec.

    1971-12-01T10:54:27Z → 1971-12-02T07:48:07Z

  2. 02

    Kāla

    Pradoṣa is 2 muhūrtas after sunset: 16:57–18:51 on the 1st, 16:56–18:51 on the 2nd.

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

  3. 03

    Rule

    Pūrṇimā must be present during pradoṣa. It covers 0 of 115 minutes on the 1st and 0 of 115 on the 2nd.

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

  4. 04

    Tie-break

    Neither evening qualifies. The day the tithi falls on is taken.

    priority: unstated → tithi-day · margin 183 s < 300 s

  5. 05

    Ruling

    Dattātreyotpatti, Baoding, 1971: Wednesday 1 December.

    confidence: boundary (margin, absent-unstated)

Say it like this

In Baoding, Dattātreyotpatti (Datta Jayanti) 1971 falls on Wednesday 1 December. Pūrṇimā runs from 18:54 on Wed 1 Dec to 15:48 on Thu 2 Dec, and reaches pradoṣa on neither day. It is 3 min 03 s from a threshold: treat the date as contested.

ahargana.org/baoding/festivals/1971/dattatreyotpatti · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingWed 1 Dec
Ahargaṇa, classicalDisc centre, no refractionWed 1 Dec
compat-drikpanchangComparison profileWed 1 Dec
No institution has a recorded ruling for Baoding.

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

The rule, as data

/rules/dattatreyotpatti · ruleset 2026.3-draft

Month
Mārgaśīrṣa, amānta
Pakṣa · aṅga
Śukla · Pūrṇimā
Kāla
Pradoṣa
Priority
Unstated
Tie-break
Longer coverage, as a boundary
Reference
CRC 1955, p. 104

“S 15 Dattatreyotpatti (pradosa).” Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 104.

The same rule, elsewhere

Twelve places, west to east. Local clock times.

PlacePūrṇimāSunset 1stCoveredSunset 2ndCoveredRuled
Los Angeles02:54 → 23:4816:43112 min16:430 min1 Dec
Chicago04:54 → 01:4816:20117 min16:200 min1 Dec
Jersey City05:54 → 02:4816:29116 min16:290 min1 Dec
Port of Spain06:54 → 03:4817:41100 min17:410 min1 Dec
London10:54 → 07:4815:55127 min15:540 min1 Dec
Durban12:54 → 09:4818:4281 min18:430 min1 Dec
Dubai14:54 → 11:4817:28107 min17:280 min1 Dec
Delhi16:24 → 13:1817:23108 min17:230 min1 Dec
Kolkata16:24 → 13:1816:51105 min16:510 min1 Dec
Singapore18:24 → 15:1818:2596 min18:250 min1 Dec
Sydney21:54 → 18:4819:500 min19:510 min1 Dec
Suva22:54 → 19:4818:290 min18:2979 min2 Dec
Profile · tradition
pac-rp@2026.1 · smarta
Rule
dattatreyotpatti@2026.3-draft
Engine · kernel
0.1.0 · de440 7eef…ea74
Boundary margin
300 s

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