Panchangam Reference

Solar and lunar Rashi ​

panchangam.rashi

Thirty-degree sidereal longitude sectors determine solar and lunar signs.

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 the selected engine's normalized sunrise Sun and Moon longitudes into twelve 30-degree sidereal signs.

Process ​

  1. Evaluate engine Sun and Moon longitude at local sunrise.
  2. For each body compute floor(longitude/30) modulo 12.
  3. Map both indices through RASHI_NAMES.

Formulae ​

Rashi index ​

text
r = floor(longitude / 30) mod 12
  • longitude: normalized sidereal body longitude
  • r: Rashi index, Mesha=0

Worked example ​

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

Inputs

  • Sun: 55.8893662040 degrees
  • Moon: 358.4708221648 degrees

Calculation

  1. floor(55.8893662040/30)=1.
  2. floor(358.4708221648/30)=11.

Result

  • Solar Rashi: Vrishabha
  • Lunar Rashi: Meena

Method notes ​

  • These are sunrise classifications, not continuous sign-ingress spans.

Contract ​

Owning layer: engine-core
Claim kind: deterministic-fact
Time basis: Longitude at local sunrise.

Inputs ​

  • engine solar and lunar longitude

Outputs ​

  • solar Rashi
  • lunar Rashi

References and evidence ​

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

Drik has representative comparison evidence; non-Drik outputs 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 ​

  • Signs follow the selected engine and ayanamsa conventions.

Implementation ​

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