Ruling · Dattātreyotpatti (Datta Jayanti) · 1948

Wednesday 15 December

Boundaryin Baoding, under the Rashtriya Panchang method. Both evenings qualify and the rule does not say which to take. 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 15 December

Taken. Both evenings qualify; the rule is silent, and this one is covered longer.

16:57 sunsetpradoṣa ends 18:53
Pūrṇimā begins 18:16:58
16:3316:5717:2117:4518:0918:3318:5719:21

36 of 116 minutes covered, the last 36

Evening of Thursday 16 December

Qualifies with 14 of 117 minutes. Not taken.

16:57 sunsetpradoṣa ends 18:54
Pūrṇimā ends 17:10:54
16:3316:5717:2117:4518:0918:3318:5719:21

14 of 117 minutes covered, the first 14

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

How it was decided

  1. 01

    Aṅga

    Pūrṇimā runs from 18:17 on Wed 15 Dec to 17:11 on Thu 16 Dec.

    1948-12-15T10:16:58Z → 1948-12-16T09:10:55Z

  2. 02

    Kāla

    Pradoṣa is 2 muhūrtas after sunset: 16:57–18:53 on the 15th, 16:57–18:54 on the 16th.

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

  3. 03

    Rule

    Pūrṇimā must be present during pradoṣa. It covers 36 of 116 minutes on the 15th and 14 of 117 on the 16th.

    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 829 s

  5. 05

    Ruling

    Dattātreyotpatti, Baoding, 1948: Wednesday 15 December.

    confidence: boundary (tie-break-unstated)

Say it like this

In Baoding, Dattātreyotpatti (Datta Jayanti) 1948 falls on Wednesday 15 December. Pūrṇimā runs from 18:17 on Wed 15 Dec to 17:11 on Thu 16 Dec and covers 36 of 116 minutes of pradoṣa that evening. It also reaches the next evening for 14 minutes; the rule does not say which to take, and the one covered longer is ruled: treat the date as contested.

ahargana.org/baoding/festivals/1948/dattatreyotpatti · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingWed 15 Dec
Ahargaṇa, classicalDisc centre, no refractionWed 15 Dec
compat-drikpanchangComparison profileWed 15 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 15thCoveredSunset 16thCoveredRuled
Los Angeles03:17 → 02:1117:45113 min17:450 min15 Dec
Chicago04:17 → 03:1116:20119 min16:200 min15 Dec
Jersey City05:17 → 04:1116:29118 min16:300 min15 Dec
Port of Spain06:17 → 05:1117:46100 min17:470 min15 Dec
London10:17 → 09:1115:51129 min15:510 min15 Dec
Durban12:17 → 11:1118:5380 min18:530 min15 Dec
Dubai14:17 → 13:1117:31107 min17:320 min15 Dec
Delhi15:47 → 14:4117:26109 min17:260 min15 Dec
Kolkata15:47 → 14:4116:54106 min16:550 min15 Dec
Singapore17:47 → 16:4118:3196 min18:310 min15 Dec
Sydney20:17 → 19:1119:022 min19:028 min16 Dec
Suva22:17 → 21:1118:370 min18:3886 min16 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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