Nakshatra Vishaghati windows

derived.vishaghati

Nakshatra-specific poison-Ghati offsets produce clipped civil-time windows.

Assurance

Level	Current statement
Documented and traceable	Yes — the canonical record includes the process and a worked example.
Regression or reproduction checked	Linked to 1 repository test file(s).
Independently source-supported	Partial support only; read the provenance note and limitations before generalizing.

Computation method

Method type: formula

Place a short window at the Nakshatra-specific Ghati offset within each observed Nakshatra span, then clip it to the Panchangam day.

Process

1. Read the configured offset Ghatis for the span's Nakshatra.
2. Scale that offset over the span's full 60-Ghati transit.
3. Set the width to four Vighatis using the day's proportional Ghati clock.
4. Discard non-overlapping windows and clip partial overlaps to sunrise or next sunrise.
5. Report both civil timestamps and sunrise-based Ghati coordinates.

Formulae

Vishaghati placement

start = N_start + N_duration*offset/60; width = 4*s_g/60

• offset: Nakshatra table value in Ghatis
• s_g: seconds per day Ghati
• N_duration: observed Nakshatra duration

Worked example

Synthetic 24-hour Ashvini span

Inputs

• Nakshatra span: 06:00 to 06:00 next day
• Ashvini offset: 50 Ghatis
• Day Ghati scale: 1,440 seconds

Calculation

1. 24h * 50/60 = 20h after Nakshatra start.
2. Four Vighatis = 4 * 1,440/60 = 96 seconds.

Result

• Vishaghati: 02:00:00-02:01:36 next day

Method notes

• Offset placement scales with the observed Nakshatra span, while width scales with the local sunrise day; these are intentionally distinct clocks.

Contract

Owning layer: derived
Claim kind: textual-rule
Time basis: Nakshatra duration mapped to the sunrise-anchored Ghati scale.

Inputs

• Nakshatra spans
• Ghati clock
• day bounds

Outputs

• Vishaghati windows in civil time and Ghatis

References and evidence

Evidence classes: textual
Verification states: partially_verified

Offsets and clipping are tested; claim-level source coverage remains grouped with mixed daily windows.

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

• Muhurtha (Electional Astrology) — B. V. Raman; UBS Publishers' Distributors, 1993, ISBN 9788185674681, 181 catalogued pages; authority type: modern_synthesis
• Muhurtha (Electional Astrology) — Chistabo re-edited derivative — B. V. Raman; re-edited by Simon (Chistabo); 2020 re-edited transcription, 78 physical PDF pages; authority type: inspected_derivative
• Muhurta Chintamani — Rama Daivajna; Undated Sanskrit text with Hindi commentary, Internet Archive identifier muhurta-chintamani-hindi; authority type: primary_text_hindi_commentary

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

• tests/test_vishaghati.py

Run the linked tests, then the complete offline contract:

python tools/verify_project.py

Public surfaces

• python-library
• mcp
• ics
• website

Limitations

• The selected offset table is tradition-specific.

Implementation

• owner: telugu_panchangam/karana_windows.py — compute_vishaghati

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