Vimśottarī antardaśā proportional timing reference
How Maha subdivides each major period into nine proportional sub-periods while preserving parent lord, sequence, boundaries, and rounding.
Timing reference · released 2026-08-18
Event definition
An antardaśā is a nested sub-period whose duration is the parent mahādaśā duration multiplied by the sub-lord’s nominal years divided by 120.
Reproducible calculation
Begin with the mahādaśā lord, follow the same cyclic nine-lord order, allocate parentDuration × subLordYears / 120 to each interval, and force the final sub-period end to equal the parent end so rounding cannot create a gap or overlap.
Required inputs
- Parent mahādaśā start and end
- Parent lord
- Nine-lord sequence and duration weights
- Timestamp rounding policy
Maha convention
Maha stores parent and sub-lord explicitly, starts the sub-period order with the parent lord, uses half-open UTC intervals, and makes the last antardaśā boundary exactly equal the containing mahādaśā boundary.
Uncertainty and edge cases
Sub-period boundaries inherit every uncertainty in the natal anchor and parent period. Repeated floating-point rounding can create drift unless calculations use one duration basis and reconcile the final boundary.
How reports may use this reference
Reports may identify the active major/sub-period pair and next transition. Narrative interpretation is compiled only from applicable reviewed rules, not generated from the two lord names.
What this does not establish
A nested period pair does not establish a more precise forecast; additional labels can increase apparent specificity without adding empirical evidence.
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.