Ruling · Durgā Navamī · 1987

Saturday 31 October

Boundaryin Shaoxing, under the Rashtriya Panchang method. A threshold is only 1 min 12 s away. Say “contested”.

Decide it for

ShaoxingDelhiKolkataSingaporeSydneyJersey City

30°00′ N 120°35′ E · Asia/Shanghai · GeoNames 1795855

The two middays

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

Midday of Friday 30 October

Navamī is absent from madhyāhna. Not taken.

madhyāhna begins 11:17  12:05 madhyāhna ends
Navamī begins 12:06:26
10:2910:5311:1711:4112:0512:2912:53

0 of 48 minutes covered

Midday of Saturday 31 October

Taken. Navamī reaches neither midday; the rule takes the second day.

madhyāhna begins 11:17  12:05 madhyāhna ends
10:2910:5311:1711:4112:0512:2912:53

0 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 12:06 on Fri 30 Oct to 10:01 on Sat 31 Oct.

    1987-10-30T04:06:26Z → 1987-10-31T02:00:47Z

  2. 02

    Kāla

    Madhyāhna is 1 ghaṭikā either side of midday: 11:17–12:05 on the 30th, 11:17–12:05 on the 31st.

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

  3. 03

    Rule

    Navamī must be present during madhyāhna. It covers 0 of 48 minutes on the 30th and 0 of 48 on the 31st.

    Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 104

  4. 04

    Tie-break

    Neither midday qualifies. The rule takes the second day.

    priority: purvaviddha → second-day · margin 72 s < 300 s

  5. 05

    Ruling

    Durgā Navamī, Shaoxing, 1987: Saturday 31 October.

    confidence: boundary (margin)

Say it like this

In Shaoxing, Durgā Navamī 1987 falls on Saturday 31 October. Navamī runs from 12:06 on Fri 30 Oct to 10:01 on Sat 31 Oct, and reaches madhyāhna on neither day. It is 1 min 12 s from a threshold: treat the date as contested.

ahargana.org/shaoxing/festivals/1987/durga-navami · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingSat 31 Oct
Ahargaṇa, classicalDisc centre, no refractionSat 31 Oct
compat-drikpanchangComparison profileFri 30 Oct
No institution has a recorded ruling for Shaoxing.

Institutional rulings are recorded with a source address, and are never edited to agree.

The rule, as data

/rules/durga-navami · ruleset 2026.3-draft

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

“S 9 Aksaya navami (purvahnavyapini), Jagaddhatri puja (Bengal), (udayavyapini one muhurta), Anla navami (Orissa), Durga navami (purvaviddha), Gauri vrata.” Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 104.

The same rule, elsewhere

Twelve places, west to east. Local clock times.

PlaceNavamīMadhyāhna 30thCoveredMadhyāhna 31stCoveredRuled
Los Angeles20:06 → 18:0111:1248 min11:120 min30 Oct
Chicago22:06 → 20:0111:1048 min11:100 min30 Oct
Jersey City23:06 → 21:0111:1648 min11:160 min30 Oct
Port of Spain00:06 → 22:0111:2648 min11:260 min30 Oct
London04:06 → 02:0111:2048 min11:200 min30 Oct
Durban06:06 → 04:0111:1648 min11:160 min30 Oct
Dubai08:06 → 06:0111:3848 min11:380 min30 Oct
Delhi09:36 → 07:3111:4148 min11:410 min30 Oct
Kolkata09:36 → 07:3110:5648 min10:560 min30 Oct
Singapore12:06 → 10:0112:2448 min12:240 min30 Oct
Sydney15:06 → 13:0112:150 min12:1546 min31 Oct
Suva16:06 → 14:0111:260 min11:2648 min31 Oct
Profile · tradition
pac-rp@2026.1 · smarta
Rule
durga-navami@2026.3-draft
Engine · kernel
0.1.0 · de440 7eef…ea74
Boundary margin
300 s

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