Ruling · Śiva Śayanotsava · 1921

Tuesday 19 July

Determinatein Chattogram, under the Rashtriya Panchang method. Clear of every threshold by 473 minutes.

Decide it for

ChattogramDelhiKolkataSingaporeSydneyJersey City

22°20′ N 91°50′ E · Asia/Dhaka · GeoNames 1205733

The two evenings

One ghaṭī is 24 minutes. Pradoṣa is 2 muhūrtas after sunset.

Evening of Monday 18 July

Pūrṇimā is absent from pradoṣa. Not taken.

18:32 sunsetpradoṣa ends 19:57
18:0818:3218:5619:2019:4420:0820:32

0 of 85 minutes covered

Evening of Tuesday 19 July

Taken. The only evening Pūrṇimā reaches.

18:32 sunsetpradoṣa ends 19:57
18:0818:3218:5619:2019:4420:0820:32

85 of 85 minutes covered

Pūrṇimā presentPradoṣa, the window the rule readsThe instant the tithi begins or ends

How it was decided

  1. 01

    Aṅga

    Pūrṇimā runs from 03:51 on Tue 19 Jul to 06:00 on Wed 20 Jul.

    1921-07-18T21:57:35Z → 1921-07-20T00:07:20Z

  2. 02

    Kāla

    Pradoṣa is 2 muhūrtas after sunset: 18:32–19:57 on the 18th, 18:32–19:57 on the 19th.

    pradosha: night-muhurta-1-2 · sunrise and sunset: upper limb, 31′ + 16′

  3. 03

    Rule

    Pūrṇimā must be present during pradoṣa. It covers 0 of 85 minutes on the 18th and 85 of 85 on the 19th.

    Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 102

  4. 04

    Tie-break

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

    priority: unstated → only-day · margin 28409 s

  5. 05

    Ruling

    Śiva Śayanotsava, Chattogram, 1921: Tuesday 19 July.

    confidence: determinate

Say it like this

In Chattogram, Śiva Śayanotsava 1921 falls on Tuesday 19 July. Pūrṇimā runs from 03:51 on Tue 19 Jul to 06:00 on Wed 20 Jul and covers all of pradoṣa that evening.

ahargana.org/chattogram/festivals/1921/shiva-shayanotsava · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingTue 19 Jul
Ahargaṇa, classicalDisc centre, no refractionTue 19 Jul
compat-drikpanchangComparison profileTue 19 Jul
No institution has a recorded ruling for Chattogram.

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

The rule, as data

/rules/shiva-shayanotsava · ruleset 2026.3-draft

Month
Āṣāḍha, amānta
Pakṣa · aṅga
Śukla · Pūrṇimā
Kāla
Pradoṣa
Priority
Unstated
Tie-break
Longer coverage, as a boundary
Reference
CRC 1955, p. 102

“S 15 Guru purnima (paraviddha), Vyasa puja (paraviddha, 3 muhurtas after sunrise), Kokila vrata (sayahna vyapini). Siva sayanotsava (pradosavyapini).” Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 102.

The same rule, elsewhere

Twelve places, west to east. Local clock times.

PlacePūrṇimāSunset 18thCoveredSunset 20thCoveredRuled
Los Angeles13:58 → 16:0719:0379 min19:020 min18 Jul
Chicago16:58 → 19:0720:2273 min20:200 min18 Jul
Jersey City17:58 → 20:0720:2474 min20:230 min18 Jul
Port of Spain17:58 → 20:0718:3291 min18:320 min19 Jul
London22:58 → 01:0721:080 min21:060 min19 Jul
Durban23:58 → 02:0717:150 min17:160 min19 Jul
Dubai01:58 → 04:0719:100 min19:090 min19 Jul
Delhi03:28 → 05:3719:200 min19:190 min19 Jul
Kolkata03:28 → 05:3718:230 min18:230 min19 Jul
Singapore04:58 → 07:0718:160 min18:160 min19 Jul
Sydney07:58 → 10:0717:050 min17:060 min19 Jul
Suva09:58 → 12:0717:470 min17:470 min19 Jul
Profile · tradition
pac-rp@2026.1 · smarta
Rule
shiva-shayanotsava@2026.3-draft
Engine · kernel
0.1.0 · de440 7eef…ea74
Boundary margin
300 s

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