Ruling · Śaṅkara Jayantī · 1921

Thursday 12 May

Boundaryin Cairo, under the Rashtriya Panchang method. A threshold is only 2 min 03 s away. Say “contested”.

Decide it for

CairoDelhiKolkataSingaporeSydneyJersey City

30°04′ N 31°15′ E · Africa/Cairo · GeoNames 360630

The two middays

One ghaṭī is 24 minutes. Madhyāhna is 1 ghaṭikā either side of midday.

Midday of Wednesday 11 May

Pañcamī is absent from madhyāhna. Not taken.

madhyāhna begins 11:27  12:15 madhyāhna ends
10:3911:0311:2711:5112:1512:3913:03

0 of 48 minutes covered

Midday of Thursday 12 May

Taken. Pañcamī reaches neither midday; the rule takes the second day.

madhyāhna begins 11:27  12:15 madhyāhna ends
Pañcamī ends 11:25:22
10:3911:0311:2711:5112:1512:3913:03

0 of 48 minutes covered

Pañcamī presentMadhyāhna, the window the rule readsThe instant the tithi begins or ends

How it was decided

  1. 01

    Aṅga

    Pañcamī runs from 14:01 on Wed 11 May to 11:25 on Thu 12 May.

    1921-05-11T12:01:25Z → 1921-05-12T09:25:22Z

  2. 02

    Kāla

    Madhyāhna is 1 ghaṭikā either side of midday: 11:27–12:15 on the 11th, 11:27–12:15 on the 12th.

    madhyahna: midday-pm-1-ghatika · sunrise and sunset: upper limb, 31′ + 16′

  3. 03

    Rule

    Pañcamī must be present during madhyāhna. It covers 0 of 48 minutes on the 11th and 0 of 48 on the 12th.

    Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 102

  4. 04

    Tie-break

    Neither midday qualifies. The rule takes the second day.

    priority: unstated → second-day · margin 123 s < 300 s

  5. 05

    Ruling

    Śaṅkara Jayantī, Cairo, 1921: Thursday 12 May.

    confidence: boundary (margin)

Say it like this

In Cairo, Śaṅkara Jayantī 1921 falls on Thursday 12 May. Pañcamī runs from 14:01 on Wed 11 May to 11:25 on Thu 12 May, and reaches madhyāhna on neither day. It is 2 min 03 s from a threshold: treat the date as contested.

ahargana.org/cairo/festivals/1921/shankara-jayanti · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingThu 12 May
Ahargaṇa, classicalDisc centre, no refractionThu 12 May
compat-drikpanchangComparison profileThu 12 May
No institution has a recorded ruling for Cairo.

Institutional rulings are recorded with a source address, and are never edited to agree.

The rule, as data

/rules/shankara-jayanti · ruleset 2026.3-draft

Month
Vaiśākha, amānta
Pakṣa · aṅga
Śukla · Pañcamī
Kāla
Madhyāhna
Priority
Unstated
Tie-break
Longer coverage, as a boundary
Reference
CRC 1955, p. 102

“S 5 Sankara jayanti.” Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 102.

The same rule, elsewhere

Twelve places, west to east. Local clock times.

PlacePañcamīMadhyāhna 11thCoveredMadhyāhna 12thCoveredRuled
Los Angeles04:01 → 01:2511:2548 min11:250 min11 May
Chicago07:01 → 04:2512:2348 min12:230 min11 May
Jersey City08:01 → 05:2512:2948 min12:290 min11 May
Port of Spain08:01 → 05:2511:3848 min11:380 min11 May
London13:01 → 10:2512:3320 min12:330 min11 May
Durban14:01 → 11:2511:280 min11:280 min12 May
Dubai16:01 → 13:2511:510 min11:5148 min12 May
Delhi17:31 → 14:5511:540 min11:5348 min12 May
Kolkata17:31 → 14:5511:090 min11:0948 min12 May
Singapore19:01 → 16:2511:370 min11:3748 min12 May
Sydney22:01 → 19:2511:270 min11:2748 min12 May
Suva00:01 → 21:2511:380 min11:3848 min12 May
Profile · tradition
pac-rp@2026.1 · smarta
Rule
shankara-jayanti@2026.3-draft
Engine · kernel
0.1.0 · de440 7eef…ea74
Boundary margin
300 s

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