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How to Calculate the Current Dasha: A Worked Example

Reproduce a current Vimshottari period from Moon longitude, birth balance and interval lookup. Includes the often-missed elapsed subperiod calculation.

Names and related terms
Current dasha

Editorially reviewed: · Reviewed by OpenFate · Editorial Methodology

Overview

The current dasha is the interval containing a specified target instant, not an estimate based on age alone. Compute the birth Moon’s nakshatra and remaining mahadasha balance, reconstruct the full parent sequence, and then locate the target within its main and subperiod intervals.

At a glance

Inputs
Birth timestamp, Moon longitude, ayanamsa and target instant
Year basis
Declare days per model year
Interval rule here
Start inclusive; end exclusive
Critical detail
First parent period can start before birth

What calculation comes before the lookup?

Normalize the birth record to a verified instant and calculate the sidereal Moon. Its nakshatra supplies the starting ruler; its traversed fraction times the full ruler length gives the elapsed parent duration. Subtract that duration from birth to reconstruct the full mahadasha start.

Expand the nine antardashas from that full start, not from birth, with parent years × child years / 120. Advance the main periods cyclically and find the interval containing the requested instant. Keep rounding out of intermediate boundaries and state the timezone used for display.

A birth already inside Moon/Saturn

Use a synthetic Moon at 46°40′ sidereal longitude, halfway through Rohini’s 40°–53°20′ span. Its full Moon period is ten model years; birth is five years after its full start, leaving five. Moon antardashas through Jupiter end at elapsed 4.25 years.

Moon/Saturn then runs from 4.25 to 35/6 years, so birth at elapsed 5 lies inside it. One model year after birth is elapsed 6, inside Moon/Mercury, whose interval is 35/6 to 7.25. Restarting Moon/Moon at birth would miss both answers.

How do I check calendar boundaries and uncertainty?

These example ages are model-year offsets, not calendar anniversaries. Under the locally reviewed 365.25-day policy, multiply each offset by 365.25 days before adding it to the verified timestamp. A 360-day model needs its own explicitly labelled conversion; do not mix the two.

At an exact boundary, assign the instant to the interval beginning there under the stated start-inclusive rule. If the birth-time or lunar-position uncertainty straddles a boundary, return the candidate labels rather than a false exact result. This lookup verifies a timing label, not a future event.

Sources and editorial basis

  1. P. V. R. Narasimha Rao: Vedic Astrology — An Integrated Approach
    Rao, Vedic Astrology: An Integrated Approach. §1.3.6 / Table 2, pp. 10–11: equal nakshatra spans and Rohini longitude; §16.2 / Table 38, pp. 210–211: Moon lord, 10-year duration, remaining balance and year conventions; §16.3, p. 212: antardasha order and proportions. The full-parent interval lookup and half-open boundary convention are original explicit arithmetic. These passages document named traditional methods, not scientific validity. Examples are synthetic, not verified birth observations.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. OpenFate Vedic implementation: local source review, 2026-09-08
    Read-only source review on 2026-09-08: openfate/app/modules/vedic/logic/policy.ts, VEDIC_ENGINE_POLICY (vedic-policy-1.1.0): Vimshottari only and 365.25-day years; math.ts, horaSign and computeVargaSigns: named D2 Sun/Leo and Moon/Cancer mapping plus D6/D9/D10/D24. This verifies the local declared implementation, not current production or alternate-method UI support.An editorial review of local policy and calculation source files, not an independently accessible publication or proof of the deployed version. Implementation limitations and discrepancies remain separate from traditional arithmetic.
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