Panchangam Reference

Abhijit Muhurta window ​

panchangam.abhijit-muhurta

The midday auspicious interval is derived proportionally from daytime length, except on Wednesday.

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: formula

Divide the sunrise-to-sunset interval into 15 equal Muhurta-length parts and return the eighth, middle part, except that the selected convention suppresses it on Wednesday.

Process ​

  1. If the weekday is Wednesday, return null and do not construct an Abhijit window.
  2. Subtract sunrise from sunset to obtain the local daylight duration D.
  3. Take the arithmetic midpoint M of the sunrise and sunset instants.
  4. Set the half-width H to D / 30, which makes the complete interval 2H = D / 15.
  5. Return M - H as the start and M + H as the end; the engine stores both as UTC instants and presentation layers convert them to local civil time.

Formulae ​

Daylight duration and midpoint ​

text
D = T_set - T_rise
M = (T_rise + T_set) / 2
  • T_rise: computed sunrise instant for the location and date
  • T_set: computed sunset instant for the location and date
  • D: elapsed sunrise-to-sunset duration
  • M: arithmetic midpoint of the sunrise-to-sunset interval

Abhijit interval ​

text
H = D / 30
start = M - H
end = M + H
end - start = D / 15
  • H: half of one daytime Muhurta
  • start: beginning of the eighth daytime part
  • end: end of the eighth daytime part

Worked example ​

Hyderabad, 2026-06-11, Drik Ganita (Asia/Kolkata) ​

Inputs

  • Weekday: Thursday, so the Wednesday exclusion does not apply
  • Sunrise: 05:41:11 IST (00:11:11 UTC)
  • Sunset: 18:50:12 IST (13:20:12 UTC)

Calculation

  1. D = 18:50:12 - 05:41:11 = 13:09:01 = 47,341 seconds.
  2. M = (05:41:11 + 18:50:12) / 2 = 12:15:41.5 IST.
  3. H = 47,341 / 30 = 1,578.033 seconds, or 00:26:18.033.
  4. start = 12:15:41.5 - 00:26:18.033 = 11:49:23.467 IST; end = 12:15:41.5 + 00:26:18.033 = 12:41:59.533 IST.

Result

  • Engine instants at whole-second precision: 11:49:23–12:41:59 IST.
  • Published-reference comparison in the regression test: 11:50–12:42, within the test's one-minute display tolerance.
  • Total duration: 52 minutes 36 seconds, equal to daylight duration / 15.

Method notes ​

  • This midpoint is derived from sunrise and sunset; it is not a separate calculation of the Sun's meridian transit.
  • The cited published reference also cautions against marriage and Upanayana during Abhijit; this low-level window function does not evaluate activity suitability.
  • A criterion-level primary textual verse or edition locator has not yet been registered.

Contract ​

Owning layer: engine-core
Claim kind: textual-rule
Time basis: Proportional local daytime centered on the arithmetic midpoint between sunrise and sunset.

Inputs ​

  • sunrise
  • sunset
  • weekday

Outputs ​

  • Abhijit start/end or null

References and evidence ​

Evidence classes: published_panchangam
Verification states: partially_verified

The maintained implementation formula and Wednesday convention have a direct published-Panchangam reference and a representative output comparison. This is not a primary textual locator or a broad multi-city comparison set.

panchangam.abhijit_muhurta_method ​

Evidence class: published_panchangam
Verification state: partially_verified
Locator: Section 'About Abhijit Muhurat': the second paragraph defines Abhijit as the eighth of 15 equal sunrise-to-sunset parts; the following example derives 11:40-12:20 for a 06:00-18:00 day; the final paragraph records the Wednesday exclusion
Last reviewed: 2026-08-28
Scope: Supports the maintained daylight-division formula and selected Wednesday convention. It is a published-Panchangam reference rather than a primary textual edition. The repository currently has one explicit location/date comparison for the displayed window, so this does not establish exhaustive multi-city output verification or universal activity suitability.

Sources ​

  • Abhijit Muhurat — Drik Panchang; Web reference page, accessed 2026-08-28; authority type: published_panchangam

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 ​

  • Wednesday returns no Abhijit window under the selected convention.
  • The registered external method reference is a published Panchangam, not a primary textual edition.
  • The low-level computation does not enforce activity-specific restrictions such as marriage or Upanayana suitability.

Implementation ​

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