Ruling · Dattātreyotpatti (Datta Jayanti) · 1917

Thursday 27 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

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 Thursday 27 December

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

17:02 sunsetpradoṣa ends 18:59
Pūrṇimā begins 17:45:31
16:3817:0217:2617:5018:1418:3819:0219:26

73 of 117 minutes covered, the last 73

Evening of Friday 28 December

Qualifies with 48 of 116 minutes. Not taken.

17:03 sunsetpradoṣa ends 18:59
Pūrṇimā ends 17:51:17
16:3917:0317:2717:5118:1518:3919:0319:27

48 of 116 minutes covered, the first 48

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

How it was decided

  1. 01

    Aṅga

    Pūrṇimā runs from 17:46 on Thu 27 Dec to 17:51 on Fri 28 Dec.

    1917-12-27T09:45:31Z → 1917-12-28T09:51:18Z

  2. 02

    Kāla

    Pradoṣa is 2 muhūrtas after sunset: 17:02–18:59 on the 27th, 17:03–18:59 on the 28th.

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

  3. 03

    Rule

    Pūrṇimā must be present during pradoṣa. It covers 73 of 117 minutes on the 27th and 48 of 116 on the 28th.

    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 2595 s

  5. 05

    Ruling

    Dattātreyotpatti, Baoding, 1917: Thursday 27 December.

    confidence: boundary (tie-break-unstated)

Say it like this

In Baoding, Dattātreyotpatti (Datta Jayanti) 1917 falls on Thursday 27 December. Pūrṇimā runs from 17:46 on Thu 27 Dec to 17:51 on Fri 28 Dec and covers 73 of 117 minutes of pradoṣa that evening. It also reaches the next evening for 48 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/1917/dattatreyotpatti · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingThu 27 Dec
Ahargaṇa, classicalDisc centre, no refractionThu 27 Dec
compat-drikpanchangComparison profileThu 27 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 27thCoveredSunset 28thCoveredRuled
Los Angeles01:46 → 01:5116:51113 min16:510 min27 Dec
Chicago03:46 → 03:5116:26119 min16:270 min27 Dec
Jersey City04:46 → 04:5116:35118 min16:360 min27 Dec
Port of Spain05:46 → 05:5117:52100 min17:530 min27 Dec
London09:46 → 09:5115:57129 min15:570 min27 Dec
Durban11:46 → 11:5118:5880 min18:590 min27 Dec
Dubai13:27 → 13:3217:18107 min17:190 min27 Dec
Delhi15:16 → 15:2117:32110 min17:320 min27 Dec
Kolkata15:16 → 15:2117:00106 min17:010 min27 Dec
Singapore16:46 → 16:5118:0796 min18:070 min27 Dec
Sydney19:46 → 19:5119:0839 min19:0843 min28 Dec
Suva21:46 → 21:5118:430 min18:4486 min28 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

About Ahargaṇa