Ruling · Dattātreyotpatti (Dattātreya Jayantī) · 2021

Saturday 18 December

Determinatein Baoding, under the Rashtriya Panchang method. Clear of every threshold by 263 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 Saturday 18 December

Taken. The only evening Pūrṇimā reaches.

16:58 sunsetpradoṣa ends 18:54
16:3416:5817:2217:4618:1018:3418:5819:22

117 of 117 minutes covered

Evening of Sunday 19 December

Pūrṇimā is absent from pradoṣa. Not taken.

16:58 sunsetpradoṣa ends 18:55
16:3416:5817:2217:4618:1018:3418:5819:22

0 of 117 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 09:55 on Sat 18 Dec to 12:36 on Sun 19 Dec.

    2021-12-18T01:54:51Z → 2021-12-19T04:35:31Z

  2. 02

    Kāla

    Pradoṣa is 2 muhūrtas after sunset: 16:58–18:54 on the 18th, 16:58–18:55 on the 19th.

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

  3. 03

    Rule

    Pūrṇimā must be present during pradoṣa. It covers 117 of 117 minutes on the 18th and 0 of 117 on the 19th.

    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 15759 s

  5. 05

    Ruling

    Dattātreyotpatti, Baoding, 2021: Saturday 18 December.

    confidence: determinate

Say it like this

In Baoding, Dattātreyotpatti (Datta Jayanti) 2021 falls on Saturday 18 December. Pūrṇimā runs from 09:55 on Sat 18 Dec to 12:36 on Sun 19 Dec and covers all of pradoṣa that evening.

ahargana.org/baoding/festivals/2021/dattatreyotpatti · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingSat 18 Dec
Ahargaṇa, classicalDisc centre, no refractionSat 18 Dec
compat-drikpanchangComparison profileSat 18 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 18thCoveredSunset 19thCoveredRuled
Los Angeles17:55 → 20:3616:46113 min16:470 min18 Dec
Chicago19:55 → 22:3616:21119 min16:220 min18 Dec
Jersey City20:55 → 23:3616:30118 min16:310 min18 Dec
Port of Spain21:55 → 00:3617:48100 min17:480 min18 Dec
London01:55 → 04:3615:52130 min15:520 min18 Dec
Durban03:55 → 06:3618:5480 min18:550 min18 Dec
Dubai05:55 → 08:3617:33107 min17:330 min18 Dec
Delhi07:25 → 10:0617:27110 min17:270 min18 Dec
Kolkata07:25 → 10:0616:56106 min16:560 min18 Dec
Singapore09:55 → 12:3619:0296 min19:030 min18 Dec
Sydney12:55 → 15:3620:0477 min20:040 min18 Dec
Suva13:55 → 16:3618:3986 min18:400 min18 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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