Ruling · Rādhāṣṭamī · 1977

Tuesday 20 September

Determinatein Tehran, under the Rashtriya Panchang method. Clear of every threshold by 501 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 19 September

Aṣṭamī is absent from madhyāhna. Not taken.

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

0 of 48 minutes covered

Midday of Tuesday 20 September

Taken. The only midday Aṣṭamī reaches.

madhyāhna begins 12:34  13:22 madhyāhna ends
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 23:55 on Mon 19 Sep to 21:42 on Tue 20 Sep.

    1977-09-19T19:25:01Z → 1977-09-20T17:12:23Z

  2. 02

    Kāla

    Madhyāhna is 1 ghaṭikā either side of midday: 12:34–13:22 on the 19th, 12:34–13:22 on the 20th.

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

  3. 03

    Rule

    Aṣṭamī must be present during madhyāhna. It covers 0 of 48 minutes on the 19th and 48 of 48 on the 20th.

    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 30051 s

  5. 05

    Ruling

    Rādhāṣṭamī, Tehran, 1977: Tuesday 20 September.

    confidence: determinate

Say it like this

In Tehran, Rādhāṣṭamī 1977 falls on Tuesday 20 September. Aṣṭamī runs from 23:55 on Mon 19 Sep to 21:42 on Tue 20 Sep and covers all of madhyāhna that midday.

ahargana.org/tehran/festivals/1977/radhashtami · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingTue 20 Sep
Ahargaṇa, classicalDisc centre, no refractionTue 20 Sep
compat-drikpanchangComparison profileTue 20 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 19thCoveredMadhyāhna 20thCoveredRuled
Los Angeles12:25 → 10:1212:2245 min12:220 min19 Sep
Chicago14:25 → 12:1212:200 min12:200 min20 Sep
Jersey City15:25 → 13:1212:260 min12:2547 min20 Sep
Port of Spain15:25 → 13:1211:360 min11:3548 min20 Sep
London20:25 → 18:1212:300 min12:2948 min20 Sep
Durban21:25 → 19:1211:260 min11:2648 min20 Sep
Dubai23:25 → 21:1211:480 min11:4848 min20 Sep
Delhi00:55 → 22:4211:510 min11:5048 min20 Sep
Kolkata00:55 → 22:4211:060 min11:0648 min20 Sep
Singapore02:55 → 00:4212:040 min12:0448 min20 Sep
Sydney05:25 → 03:1211:250 min11:2548 min20 Sep
Suva07:25 → 05:1211:360 min11:3648 min20 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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