Ruling · Dattātreyotpatti (Datta Jayanti) · 1986

Monday 15 December

Determinatein Baoding, under the Rashtriya Panchang method. Clear of every threshold by 113 minutes.

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 Monday 15 December

Taken. The only evening Pūrṇimā reaches.

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

116 of 116 minutes covered

Evening of Tuesday 16 December

Pūrṇimā is absent from pradoṣa. Not taken.

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

0 of 116 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 12:36 on Mon 15 Dec to 15:04 on Tue 16 Dec.

    1986-12-15T04:35:59Z → 1986-12-16T07:04:25Z

  2. 02

    Kāla

    Pradoṣa is 2 muhūrtas after sunset: 16:57–18:53 on the 15th, 16:57–18:53 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 116 of 116 minutes on the 15th and 0 of 116 on the 16th.

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

  4. 04

    Tie-break

    Only one evening qualifies. No tie-break is needed.

    priority: unstated → only-day · margin 6752 s

  5. 05

    Ruling

    Dattātreyotpatti, Baoding, 1986: Monday 15 December.

    confidence: determinate

Say it like this

In Baoding, Dattātreyotpatti (Datta Jayanti) 1986 falls on Monday 15 December. Pūrṇimā runs from 12:36 on Mon 15 Dec to 15:04 on Tue 16 Dec and covers all of pradoṣa that evening.

ahargana.org/baoding/festivals/1986/dattatreyotpatti · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingMon 15 Dec
Ahargaṇa, classicalDisc centre, no refractionMon 15 Dec
compat-drikpanchangComparison profileMon 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 Angeles20:36 → 23:0416:45113 min16:450 min15 Dec
Chicago22:36 → 01:0416:20119 min16:200 min15 Dec
Jersey City23:36 → 02:0416:29118 min16:300 min15 Dec
Port of Spain00:36 → 03:0417:46100 min17:470 min15 Dec
London04:36 → 07:0415:51129 min15:510 min15 Dec
Durban06:36 → 09:0418:5280 min18:530 min15 Dec
Dubai08:36 → 11:0417:31107 min17:320 min15 Dec
Delhi10:06 → 12:3417:26109 min17:260 min15 Dec
Kolkata10:06 → 12:3416:54106 min16:550 min15 Dec
Singapore12:36 → 15:0419:0196 min19:010 min15 Dec
Sydney15:36 → 18:0420:0277 min20:020 min15 Dec
Suva16:36 → 19:0418:3786 min18:3827 min15 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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