Panchangam Reference

Day and night Choghadiya ​

panchangam.choghadiya

Weekday-specific sequences label eight proportional day and night segments.

Assurance ​

LevelCurrent statement
Documented and traceableYes — the canonical record includes the process and a worked example.
Regression or reproduction checkedLinked to 2 repository test file(s).
Independently source-supportedPartial support only; read the provenance note and limitations before generalizing.

Computation method ​

Method type: decision-table

Split daylight and night into eight equal intervals and label them from weekday-specific sequences; Python owns exact daytime instants and the browser owns the minute-based night fallback.

Process ​

  1. Select the eight daytime labels for weekday index 0=Sunday through 6=Saturday.
  2. Set daytime block length to (sunset - sunrise) / 8 and construct eight contiguous windows.
  3. For the browser night fallback, treat next sunrise as minutes after midnight by adding 1,440, then divide sunset-to-next-sunrise into eight.
  4. Rotate the seven-name night cycle from the weekday's configured start name and round rendered minute boundaries.

Formulae ​

Equal day or night block ​

text
block = (period_end - period_start) / 8
start_i = period_start + i * block
end_i = period_start + (i + 1) * block
  • i: zero-based block 0 through 7
  • period: sunrise-to-sunset or sunset-to-next-sunrise

Worked example ​

Hyderabad daytime, Thursday 2026-06-11 ​

Inputs

  • Sunrise: 05:41:11 IST
  • Sunset: 18:50:12 IST
  • Thursday labels: Shubh, Rog, Udveg, Char, Labh, Amrit, Kaal, Shubh

Calculation

  1. Daylight 13:09:01 divided by 8 gives 01:38:37.625 per block.
  2. Apply the Thursday label at each contiguous boundary.

Result

  • First block: Shubh 05:41:11-07:19:48 IST
  • Fourth block: Char 10:37:04-12:15:41 IST
  • Eighth block: Shubh 17:11:34-18:50:12 IST

Method notes ​

  • The Python record does not return night Choghadiya; the browser fallback uses HH:MM inputs and rounded minutes.
  • The table's criterion-level textual locator remains grouped and incomplete.

Contract ​

Owning layer: engine-core
Claim kind: textual-rule
Time basis: Eight equal local-day parts and eight equal local-night parts.

Inputs ​

  • weekday
  • sunrise
  • sunset
  • next sunrise

Outputs ​

  • named proportional day and night windows

References and evidence ​

Evidence classes: textual, published_panchangam
Verification states: partially_verified

Day values have representative comparisons; browser-owned night extension is regression-tested through UI contracts.

panchangam.mixed_daily_windows ​

Evidence class: textual
Verification state: partially_verified
Locator: B. V. Raman, Chapter III, Nakshatra Tyajyakala table, inspected in the 2020 Chistabo derivative at internal printed p. 7 (physical PDF p. 10), and Chapter V section 7, Durmuhurta, internal printed p. 13 (physical PDF p. 16); regional tables remain regression-pinned
Last reviewed: 2026-09-04
Scope: The auspicious, inauspicious and Choghadiya response objects are mixed containers. Raman supports the four-Ghati Nakshatra Tyajyakala concept and his printed Durmuhurta scheme, but the project's regional weekday tables are not identical to Raman's table and the remaining Brahma Muhurta, Abhijit, Amrita Kalam, Rahu Kalam, Gulika, Yamagandam and Choghadiya components do not yet have criterion-level textual claims. This state records partial evidence, not umbrella verification.

Sources ​

The complete machine-readable source registry is available in provenance.json. A regression fixture or same-code reproduction is not independent verification.

Reproduce and review ​

Run the linked tests, then the complete offline contract:

bash
python tools/verify_project.py

Public surfaces ​

  • python-library
  • mcp
  • ics
  • website

Limitations ​

  • The browser computes the night sequence separately from the Python day sequence.

Implementation ​

This route is generated from computations.json. Edit the registry and canonical reference prose in the same pull request as a behavior change.