Vimśottarī birth balance calculation
How the natal Moon’s elapsed nakṣatra fraction selects the opening lord and determines the unexpired portion of the first Vimśottarī period.
Timing reference · released 2026-08-18
Event definition
The birth balance is the unexpired fraction of the mahādaśā ruled by the natal Moon’s nakṣatra. It anchors the entire reported 120-year chronology to the birth instant.
Reproducible calculation
Convert the natal Moon to Lahiri-sidereal longitude, identify its nakṣatra and ruler, solve the Moon’s actual ingress and egress times for that nakṣatra, divide elapsed stay time by total stay time, and apply the unelapsed fraction to the ruler’s nominal duration.
Required inputs
- Birth UTC instant
- Natal Moon ephemeris
- Lahiri ayanāṁśa implementation
- Nakṣatra ruler sequence
- Declared year length
Maha convention
Maha uses actual solved nakṣatra stay time rather than assuming the Moon moves at constant angular speed. The result retains ingress, egress, elapsed fraction, starting lord, balance in years, UTC boundaries, and software version.
Uncertainty and edge cases
Moon or birth-time uncertainty near a nakṣatra boundary can change the starting lord. Elsewhere it shifts the opening balance continuously; reports should propagate the plausible time interval rather than print unsupported precision.
How reports may use this reference
The birth report exposes the starting lord, balance, and solved nakṣatra timestamps so the subsequent chronology can be reproduced independently.
What this does not establish
A precise opening balance does not establish that the daśā system predicts events or that its conventional lords cause life outcomes.
Calculation and convention sources
Sources establish astronomical states or a declared chronology convention. They do not establish predictive meaning.
- Vimśottarī daśā calculation convention
Bṛhat Parāśara Horā Śāstra tradition · Calculation locator: chapters 46 and 51; passage review pending
The conventional nine-lord order, 120-year duration, natal balance concept, and proportional sub-period structure used by the implementation.
Boundary: Translation provenance and excerpt rights have not passed Maha’s passage registry. The source is used as a calculation locator only; no passage or prediction is republished.
- Astronomy Engine
Don Cross (cosinekitty) · 2.1.19
Locally computed planetary longitudes, moon phases, eclipses, and search primitives used by Maha’s deterministic calculation layer.
Boundary: Library output is a computed astronomical result. Its reproducibility does not validate a symbolic or predictive meaning.