Ruling · Mahānavamī · 2018

Wednesday 17 October

Determinatein Tehran, under the Rashtriya Panchang method. Clear of every threshold by 35 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 Wednesday 17 October

Taken. Both middays qualify; the rule takes the first.

madhyāhna begins 11:25  12:13 madhyāhna ends
Navamī begins 10:50:06
10:3711:0111:2511:4912:1312:3713:01

48 of 48 minutes covered

Midday of Thursday 18 October

Qualifies with 48 of 48 minutes. Not taken.

madhyāhna begins 11:25  12:13 madhyāhna ends
10:3711:0111:2511:4912:1312:3713:01

48 of 48 minutes covered

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

How it was decided

  1. 01

    Aṅga

    Navamī runs from 10:50 on Wed 17 Oct to 13:29 on Thu 18 Oct.

    2018-10-17T07:20:06Z → 2018-10-18T09:59:05Z

  2. 02

    Kāla

    Madhyāhna is 1 ghaṭikā either side of midday: 11:25–12:13 on the 17th, 11:25–12:13 on the 18th.

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

  3. 03

    Rule

    Navamī 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. 104

  4. 04

    Tie-break

    Both middays qualify. Pūrvaviddhā: the first is taken.

    priority: purvaviddha → purvaviddha · margin 2121 s

  5. 05

    Ruling

    Mahānavamī, Tehran, 2018: Wednesday 17 October.

    confidence: determinate

Say it like this

In Tehran, Mahānavamī 2018 falls on Wednesday 17 October. Navamī runs from 10:50 on Wed 17 Oct to 13:29 on Thu 18 Oct and covers all of madhyāhna that midday. It also reaches the next midday for 48 minutes; by the rule the first midday is taken.

ahargana.org/tehran/festivals/2018/mahanavami · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingWed 17 Oct
Ahargaṇa, classicalDisc centre, no refractionWed 17 Oct
compat-drikpanchangComparison profileWed 17 Oct
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/mahanavami · ruleset 2026.3-draft

Month
Āśvina, amānta
Pakṣa · aṅga
Śukla · Navamī
Kāla
Madhyāhna
Priority
Pūrvaviddhā
Tie-break
First day
Reference
CRC 1955, p. 104

“S 9 Mahanavami (purvaviddha) (In Bengal it is observed as paraviddha covering one muhurta from sunrise).” Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 104. The Bengal reading (paraviddha, one muhūrta from sunrise) is not applied.

The same rule, elsewhere

Twelve places, west to east. Local clock times.

PlaceNavamīMadhyāhna 17thCoveredMadhyāhna 18thCoveredRuled
Los Angeles00:20 → 02:5912:1448 min12:140 min17 Oct
Chicago02:20 → 04:5912:1248 min12:110 min17 Oct
Jersey City03:20 → 05:5912:1748 min12:170 min17 Oct
Port of Spain03:20 → 05:5911:2748 min11:270 min17 Oct
London08:20 → 10:5912:2148 min12:210 min17 Oct
Durban09:20 → 11:5911:1748 min11:1742 min17 Oct
Dubai11:20 → 13:5911:4048 min11:4048 min17 Oct
Delhi12:50 → 15:2911:420 min11:4248 min18 Oct
Kolkata12:50 → 15:2910:580 min10:5848 min18 Oct
Singapore15:20 → 17:5912:260 min12:2648 min18 Oct
Sydney18:20 → 20:5912:170 min12:1748 min18 Oct
Suva19:20 → 21:5911:280 min11:2848 min18 Oct
Profile · tradition
pac-rp@2026.1 · smarta
Rule
mahanavami@2026.3-draft
Engine · kernel
0.1.0 · de440 7eef…ea74
Boundary margin
300 s

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