Ruling · Rādhāṣṭamī · 1999

Friday 17 September

Boundaryin Tehran, under the Rashtriya Panchang method. Both middays qualify and the rule does not say which to take. Say “contested”.

Decide it for

TehranDelhiKolkataSingaporeSydneyJersey City

35°42′ N 51°25′ E · Asia/Tehran · GeoNames 112931

The two middays

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

Midday of Friday 17 September

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

madhyāhna begins 12:35  13:23 madhyāhna ends
11:4712:1112:3512:5913:2313:4714:11

48 of 48 minutes covered

Midday of Saturday 18 September

Qualifies with 48 of 48 minutes. Not taken.

madhyāhna begins 12:34  13:22 madhyāhna ends
Aṣṭamī ends 13:47:08
11:4612:1012:3412:5813:2213:4614:10

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 11:22 on Fri 17 Sep to 13:47 on Sat 18 Sep.

    1999-09-17T06:51:59Z → 1999-09-18T09:17:08Z

  2. 02

    Kāla

    Madhyāhna is 1 ghaṭikā either side of midday: 12:35–13:23 on the 17th, 12:34–13:22 on the 18th.

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

  3. 03

    Rule

    Aṣṭamī must be present during madhyāhna. It covers 48 of 48 minutes on the 17th and 48 of 48 on the 18th.

    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 1487 s

  5. 05

    Ruling

    Rādhāṣṭamī, Tehran, 1999: Friday 17 September.

    confidence: boundary (tie-break-unstated)

Say it like this

In Tehran, Rādhāṣṭamī 1999 falls on Friday 17 September. Aṣṭamī runs from 11:22 on Fri 17 Sep to 13:47 on Sat 18 Sep and covers all of madhyāhna that midday. It also reaches the next midday 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/tehran/festivals/1999/radhashtami · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingFri 17 Sep
Ahargaṇa, classicalDisc centre, no refractionFri 17 Sep
compat-drikpanchangComparison profileFri 17 Sep
No institution has a recorded ruling for Tehran.

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 17thCoveredMadhyāhna 18thCoveredRuled
Los Angeles23:52 → 02:1712:2348 min12:230 min17 Sep
Chicago01:52 → 04:1712:2148 min12:200 min17 Sep
Jersey City02:52 → 05:1712:2748 min12:260 min17 Sep
Port of Spain02:52 → 05:1711:3748 min11:360 min17 Sep
London07:52 → 10:1712:3148 min12:300 min17 Sep
Durban08:52 → 11:1711:2748 min11:260 min17 Sep
Dubai10:52 → 13:1711:4948 min11:4948 min17 Sep
Delhi12:22 → 14:4711:5218 min11:5148 min18 Sep
Kolkata12:22 → 14:4711:070 min11:0748 min18 Sep
Singapore14:52 → 17:1712:350 min12:3548 min18 Sep
Sydney16:52 → 19:1711:260 min11:2648 min18 Sep
Suva18:52 → 21:1711:370 min11:3748 min18 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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