Ruling · Rādhāṣṭamī · 2099

Monday 21 September

Determinatein Tehran, under the Rashtriya Panchang method. Clear of every threshold by 600 minutes.

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 Monday 21 September

Taken. The only midday Aṣṭamī reaches.

madhyāhna begins 11:33  12:21 madhyāhna ends
10:4511:0911:3311:5712:2112:4513:09

48 of 48 minutes covered

Midday of Tuesday 22 September

Aṣṭamī is absent from madhyāhna. Not taken.

madhyāhna begins 11:33  12:21 madhyāhna ends
10:4511:0911:3311:5712:2112:4513:09

0 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 01:34 on Mon 21 Sep to 01:17 on Tue 22 Sep.

    2099-09-20T22:03:37Z → 2099-09-21T21:47:12Z

  2. 02

    Kāla

    Madhyāhna is 1 ghaṭikā either side of midday: 11:33–12:21 on the 21st, 11:33–12:21 on the 22nd.

    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 21st and 0 of 48 on the 22nd.

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

  4. 04

    Tie-break

    Only one midday qualifies. No tie-break is needed.

    priority: unstated → only-day · margin 35990 s

  5. 05

    Ruling

    Rādhāṣṭamī, Tehran, 2099: Monday 21 September.

    confidence: determinate

Say it like this

In Tehran, Rādhāṣṭamī 2099 falls on Monday 21 September. Aṣṭamī runs from 01:34 on Mon 21 Sep to 01:17 on Tue 22 Sep and covers all of madhyāhna that midday.

ahargana.org/tehran/festivals/2099/radhashtami · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingMon 21 Sep
Ahargaṇa, classicalDisc centre, no refractionMon 21 Sep
compat-drikpanchangComparison profileMon 21 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 20thCoveredMadhyāhna 21stCoveredRuled
Los Angeles15:04 → 14:4712:220 min12:2248 min21 Sep
Chicago17:04 → 16:4712:200 min12:2048 min21 Sep
Jersey City18:04 → 17:4712:260 min12:2548 min21 Sep
Port of Spain18:04 → 17:4711:360 min11:3548 min21 Sep
London23:04 → 22:4712:300 min12:2948 min21 Sep
Durban00:04 → 23:4711:260 min11:2648 min21 Sep
Dubai02:04 → 01:4711:480 min11:4848 min21 Sep
Delhi03:34 → 03:1711:510 min11:5048 min21 Sep
Kolkata03:34 → 03:1711:060 min11:0648 min21 Sep
Singapore06:04 → 05:4712:340 min12:3448 min21 Sep
Sydney08:04 → 07:4711:250 min11:2548 min21 Sep
Suva10:04 → 09:4711:360 min11:3648 min21 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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