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Lahiri Ayanamsa: Which Setting Does a Chart Use?

Identify the Lahiri mode, distinguish named variants and check near-boundary positions without treating an approximate offset as a timeless constant.

Names and related terms
Lahiri ayanamsa · Lahiri ayanamsha · Chitrapaksha ayanamsa

Editorially reviewed: · Reviewed by OpenFate · Editorial Methodology

Overview

Lahiri is a named ayanamsa convention used in sidereal charts. Its value depends on the date and implementation. Record the actual mode and calculated value instead of treating “about 24 degrees” as a fixed correction for every birth.

At a glance

Software identifier
Swiss Ephemeris SE_SIDM_LAHIRI = 1
Other labels
Lahiri 1940, VP285 and ICRC are separate modes
Date matters
The ayanamsa is evaluated for the relevant epoch
Boundary review
Use unrounded coordinates and the selected mode

Record the mode, not only a familiar name

Swiss Ephemeris lists the standard Lahiri setting and additional named Lahiri variants. They are not interchangeable strings. An app label may hide the implementation choice, so retain a version or settings receipt when available.

Chitrapaksha-related terminology can appear in discussions of Lahiri, but a “True Citra” software option is separately identified in the manual. Do not assume two differently labeled switches must return identical numbers.

A small offset difference can change the sign

In a deliberately invented subtraction exercise, tropical 54°10′ minus offset A of 24°12′ gives 29°58′, Aries. Subtract offset B of 24°08′ instead and the result is 30°02′, Taurus. These offsets are teaching values, not current or historical Lahiri measurements.

The four-arcminute input difference explains the label change without a personality argument. Keep the body, timestamp and position flags fixed before comparing two real modes. Rounding the original longitude to 54° would conceal the useful boundary information.

Does choosing Lahiri prove a reading is accurate?

A consistent mode makes the calculation reproducible. It does not establish that a symbolic interpretation predicts events. Choose a convention required by the technique or source you are studying and name it openly.

When two reports disagree, compare the actual ayanamsa, unrounded position and house convention before changing the birth record. The general ayanamsa guide explains the coordinate idea; this page is the setting-identification checklist for Lahiri specifically.

Sources and editorial basis

  1. P. V. R. Narasimha Rao: Vedic Astrology — An Integrated Approach
    Rao §§1.3.1–1.3.3, printed pp. 5–8: graha, longitude, sign and house vocabulary only. Numerical software settings and civil-time rules are supported separately by Swiss Ephemeris and IANA; the editorial checklists are not attributed to Rao.A named practitioner’s introduction to Jyotish. Used for terminology and a stated method, not universal school agreement or scientific validation. The added March 18, 2010 note describes changed views; it does not establish a fully revised 2010 edition.
  2. OpenFate Editorial Methodology
    OpenFate Editorial Methodology, stable sections #editorial-principles, #editorial-workflow, #editorial-ai, and #editorial-context. Used for the calculation/interpretation and evidence-boundary policy.OpenFate separates deterministic chart calculation, traditional interpretation, and modern editorial explanation.
  3. Swiss Ephemeris Programmer’s Manual: Time, Sidereal Modes and Houses
    Swiss Ephemeris Programmer’s Manual §§12.1–12.2: sidereal modes, Lahiri variants and consistent position flags; §§3.4 and 15: position fields and angles. Original rounded examples are teaching arithmetic, not actual ephemeris outputs.Primary software documentation for numerical time and position calculations. Sidereal modes, including named Lahiri variants, are explicit settings. The manual does not validate astrological interpretations.
  4. IANA Time Zone Database
    IANA tz database theory.html, “Scope of the tz database” and “Accuracy of the tz database”; historical limitations, especially before 1970. This source does not verify an individual birth record.The maintained source for current and historical civil-time offsets and daylight-saving transitions; it provides timekeeping facts, not astrological interpretation.
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