Ruling · Dattātreyotpatti (Datta Jayanti) · 1991

Saturday 21 December

Determinatein Baoding, under the Rashtriya Panchang method. Clear of every threshold by 32 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 Friday 20 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

Evening of Saturday 21 December

Taken. The only evening Pūrṇimā reaches.

16:59 sunsetpradoṣa ends 18:55
Pūrṇimā ends 18:23:10
16:3516:5917:2317:4718:1118:3518:5919:23

84 of 117 minutes covered, the first 84

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

How it was decided

  1. 01

    Aṅga

    Pūrṇimā runs from 21:45 on Fri 20 Dec to 18:23 on Sat 21 Dec.

    1991-12-20T13:44:38Z → 1991-12-21T10:23:11Z

  2. 02

    Kāla

    Pradoṣa is 2 muhūrtas after sunset: 16:58–18:55 on the 20th, 16:59–18:55 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 84 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 1935 s

  5. 05

    Ruling

    Dattātreyotpatti, Baoding, 1991: Saturday 21 December.

    confidence: determinate

Say it like this

In Baoding, Dattātreyotpatti (Datta Jayanti) 1991 falls on Saturday 21 December. Pūrṇimā runs from 21:45 on Fri 20 Dec to 18:23 on Sat 21 Dec and covers 84 of 117 minutes of pradoṣa that evening.

ahargana.org/baoding/festivals/1991/dattatreyotpatti · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingSat 21 Dec
Ahargaṇa, classicalDisc centre, no refractionSat 21 Dec
compat-drikpanchangComparison profileSat 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 Angeles05:45 → 02:2316:47113 min16:470 min20 Dec
Chicago07:45 → 04:2316:22119 min16:220 min20 Dec
Jersey City08:45 → 05:2316:31118 min16:320 min20 Dec
Port of Spain09:45 → 06:2317:48100 min17:490 min20 Dec
London13:45 → 10:2315:52130 min15:530 min20 Dec
Durban15:45 → 12:2318:5580 min18:560 min20 Dec
Dubai17:45 → 14:2317:3396 min17:340 min20 Dec
Delhi19:15 → 15:5317:283 min17:280 min20 Dec
Kolkata19:15 → 15:5316:560 min16:570 min20 Dec
Singapore21:45 → 18:2319:030 min19:040 min20 Dec
Sydney00:45 → 21:2320:040 min20:0577 min21 Dec
Suva01:45 → 22:2318:400 min18:4086 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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