Ruling · Rādhāṣṭamī · 1929

Wednesday 11 September

Boundaryin Cairo, under the Rashtriya Panchang method. Both middays qualify and the rule does not say which to take. 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 Tuesday 10 September

Qualifies with 25 of 48 minutes. Not taken.

madhyāhna begins 11:28  12:16 madhyāhna ends
Aṣṭamī begins 11:51:02
10:4011:0411:2811:5212:1612:4013:04

25 of 48 minutes covered, the last 25

Midday of Wednesday 11 September

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

madhyāhna begins 11:28  12:16 madhyāhna ends
10:4011:0411:2811:5212:1612:4013:04

48 of 48 minutes covered

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

How it was decided

  1. 01

    Aṅga

    Aṣṭamī runs from 11:51 on Tue 10 Sep to 14:08 on Wed 11 Sep.

    1929-09-10T09:51:03Z → 1929-09-11T12:07:45Z

  2. 02

    Kāla

    Madhyāhna is 1 ghaṭikā either side of midday: 11:28–12:16 on the 10th, 11:28–12:16 on the 11th.

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

  3. 03

    Rule

    Aṣṭamī must be present during madhyāhna. It covers 25 of 48 minutes on the 10th and 48 of 48 on the 11th.

    Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 103

  4. 04

    Tie-break

    Both middays qualify and the rule marks neither. The one covered longer is ruled, as a boundary.

    priority: unstated → greater-coverage · margin 1390 s

  5. 05

    Ruling

    Rādhāṣṭamī, Cairo, 1929: Wednesday 11 September.

    confidence: boundary (tie-break-unstated)

Say it like this

In Cairo, Rādhāṣṭamī 1929 falls on Wednesday 11 September. Aṣṭamī runs from 11:51 on Tue 10 Sep to 14:08 on Wed 11 Sep and covers all of madhyāhna that midday. It also reaches the previous midday for 25 minutes; the rule does not say which to take, and the one covered longer is ruled: treat the date as contested.

ahargana.org/cairo/festivals/1929/radhashtami · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingWed 11 Sep
Ahargaṇa, classicalDisc centre, no refractionWed 11 Sep
compat-drikpanchangComparison profileWed 11 Sep
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/radhashtami · ruleset 2026.3-draft

Month
Bhādrapada, amānta
Pakṣa · aṅga
Śukla · Aṣṭamī
Kāla
Madhyāhna
Priority
Unstated
Tie-break
Longer coverage, as a boundary
Reference
CRC 1955, p. 103

“S 8 Durvastami (purvaviddha — S 8 of saura Bhadra except Bengal), Mahalaksmi vratarambha, Radhastami (madhyahna vyapini)” Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 103.

The same rule, elsewhere

Twelve places, west to east. Local clock times.

PlaceAṣṭamīMadhyāhna 10thCoveredMadhyāhna 11thCoveredRuled
Los Angeles01:51 → 04:0811:2648 min11:250 min10 Sep
Chicago04:51 → 07:0812:2348 min12:230 min10 Sep
Jersey City05:51 → 08:0812:2948 min12:290 min10 Sep
Port of Spain05:51 → 08:0811:3948 min11:390 min10 Sep
London10:51 → 13:0812:3348 min12:3335 min10 Sep
Durban11:51 → 14:0811:2926 min11:2948 min11 Sep
Dubai13:51 → 16:0811:520 min11:5148 min11 Sep
Delhi15:21 → 17:3811:540 min11:5448 min11 Sep
Kolkata15:21 → 17:3811:100 min11:0948 min11 Sep
Singapore16:51 → 19:0811:380 min11:3748 min11 Sep
Sydney19:51 → 22:0811:290 min11:2848 min11 Sep
Suva21:51 → 00:0811:400 min11:3948 min11 Sep
Profile · tradition
pac-rp@2026.1 · smarta
Rule
radhashtami@2026.3-draft
Engine · kernel
0.1.0 · de440 7eef…ea74
Boundary margin
300 s

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