Ruling · Dattātreyotpatti (Datta Jayanti) · 1980

Sunday 21 December

Determinatein Baoding, under the Rashtriya Panchang method. Clear of every threshold by 432 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 20 December

Pūrṇimā is absent from pradoṣa. Not taken.

16:59 sunsetpradoṣa ends 18:55
16:3516:5917:2317:4718:1118:3518:5919:23

0 of 117 minutes covered

Evening of Sunday 21 December

Taken. The only evening Pūrṇimā reaches.

16:59 sunsetpradoṣa ends 18:56
16:3516:5917:2317:4718:1118:3518:5919:23

117 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 04:43 on Sun 21 Dec to 02:08 on Mon 22 Dec.

    1980-12-20T20:43:22Z → 1980-12-21T18:08:00Z

  2. 02

    Kāla

    Pradoṣa is 2 muhūrtas after sunset: 16:59–18:55 on the 20th, 16:59–18:56 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 0 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

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

    priority: unstated → only-day · margin 25933 s

  5. 05

    Ruling

    Dattātreyotpatti, Baoding, 1980: Sunday 21 December.

    confidence: determinate

Say it like this

In Baoding, Dattātreyotpatti (Datta Jayanti) 1980 falls on Sunday 21 December. Pūrṇimā runs from 04:43 on Sun 21 Dec to 02:08 on Mon 22 Dec and covers all of pradoṣa that evening.

ahargana.org/baoding/festivals/1980/dattatreyotpatti · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingSun 21 Dec
Ahargaṇa, classicalDisc centre, no refractionSun 21 Dec
compat-drikpanchangComparison profileSun 21 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 20thCoveredSunset 21stCoveredRuled
Los Angeles12:43 → 10:0816:47113 min16:480 min20 Dec
Chicago14:43 → 12:0816:22119 min16:230 min20 Dec
Jersey City15:43 → 13:0816:31118 min16:320 min20 Dec
Port of Spain16:43 → 14:0817:49100 min17:490 min20 Dec
London20:43 → 18:0815:530 min15:53130 min21 Dec
Durban22:43 → 20:0818:550 min18:5672 min21 Dec
Dubai00:43 → 22:0817:340 min17:34108 min21 Dec
Delhi02:13 → 23:3817:280 min17:29110 min21 Dec
Kolkata02:13 → 23:3816:570 min16:57106 min21 Dec
Singapore04:13 → 01:3818:340 min18:3496 min21 Dec
Sydney07:43 → 05:0820:050 min20:0577 min21 Dec
Suva08:43 → 06:0818:400 min18:4186 min21 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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