Panchangam Reference

Karana spans ​

panchangam.karana

Each six-degree Moon-Sun elongation interval is mapped to fixed or repeating Karana names.

Assurance ​

LevelCurrent statement
Documented and traceableYes — the canonical record includes the process and a worked example.
Regression or reproduction checkedLinked to 3 repository test file(s).
Independently source-supportedNot independently verified at this level; current behavior is regression-pinned.

Computation method ​

Method type: formula

Divide Moon-Sun elongation into 60 six-degree half-Tithis, solve each boundary with the selected engine, map fixed or sevenfold repeating names, and return at most two spans intersecting daylight.

Process ​

  1. Compute E = (Moon - Sun) modulo 360 at sunrise and set half-Tithi index h=floor(E/6) modulo 60.
  2. For h and the next two indices, bisect the engine elongation at h*6 and (h+1)*6 degrees.
  3. Discard a span ending before sunrise or starting after sunset.
  4. Use KARANA_FIXED when h is a fixed index; otherwise use KARANA_REPEATING[(h-1) modulo 7].
  5. Stop after two intersecting spans.

Formulae ​

Karana index ​

text
E = (M - S) mod 360
h = floor(E / 6) mod 60
  • M: engine Moon longitude
  • S: engine Sun longitude
  • h: half-Tithi index

Worked example ​

Hyderabad sunrise, 2026-06-11, Drik Ganita ​

Inputs

  • Elongation: 302.5814559608 degrees
  • Daylight: 05:41:11-18:50:12 IST

Calculation

  1. floor(302.5814559608 / 6) modulo 60 = 50.
  2. Solve consecutive six-degree crossings and retain the first two daylight-intersecting spans.
  3. Map indices through the fixed/repeating name tables.

Result

  • Bava: 00:58:16-11:52:44 IST
  • Balava: 11:52:44-22:36:44 IST; spans are not clipped to daylight

Method notes ​

  • Boundary instants and the sunrise index inherit the selected engine's longitude model.

Contract ​

Owning layer: engine-core
Claim kind: deterministic-fact
Time basis: Sunrise-anchored day with crossings solved in UTC Julian day.

Inputs ​

  • Moon-Sun elongation over the Panchangam day

Outputs ​

  • Karana names and boundary instants

References and evidence ​

Evidence classes: astronomical, textual
Verification states: partially_verified, engine_pinned

Drik has representative comparisons; non-Drik spans are engine-pinned.

drik.sidereal_positions ​

Evidence class: astronomical
Verification state: partially_verified
Locator: Swiss Ephemeris Programmer's Documentation sections 3, 5.8 and 12.2 for calc_ut, sidereal flags and ayanamsa modes; representative date checks in tests/test_drik_engine.py and tests/test_ayanamsa.py
Last reviewed: 2026-08-27
Scope: Traces the Drik longitude API and preserves representative outputs. The current register does not contain an exhaustive independently published position-and-transition fixture, and it establishes no interpretive doctrine.

Sources ​

  • Swiss Ephemeris — Astrodienst; Swiss Ephemeris 2.10 Programmer's Documentation and pyswisseph runtime used by the repository; authority type: astronomical_reference
  • Drik Panchang day and festival pages — Drik Panchang; Location- and date-specific web pages; authority type: published_panchangam

panchangam.non_drik_engine_outputs ​

Evidence class: astronomical
Verification state: engine_pinned
Locator: tests/test_surya_siddhanta_engine.py and tests/test_vakya_engine.py

Scope: Regression tests preserve the current Surya Siddhanta and Vakya Pancha-Anga and sky-event outputs. No independent published-Panchangam comparison set is registered, so engine-pinned output must not be described as externally verified.

Sources ​

  • No external source is registered for this claim.

panchangam.calendar_semantics ​

Evidence class: textual
Verification state: needs_locator
Locator: No precise locator is registered.

Scope: Samvatsara, Ayana, Ritu, lunar-month, Paksha, weekday and Rasi labels combine astronomical calculations with calendar rollover conventions. They require criterion-level locators and regional-scope notes; astronomical correctness alone does not verify the naming convention.

Sources ​

  • Muhurtha (Electional Astrology) — B. V. Raman; UBS Publishers' Distributors, 1993, ISBN 9788185674681, 181 catalogued pages; authority type: modern_synthesis

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 ​

  • Boundary times inherit the selected engine's longitude model.

Implementation ​

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