Moon period in the Vimśottarī chronology
The calculation role of Moon in the nine-lord Vimśottarī sequence, including its 10-year nominal mahādaśā duration and proportional sub-period timing.
Timing reference · released 2026-08-18
Event definition
Moon is one member of the fixed Vimśottarī order Ketu, Venus, Sun, Moon, Mars, Rahu, Jupiter, Saturn, and Mercury. Its nominal mahādaśā allocation is 10 years within the conventional 120-year cycle.
Reproducible calculation
Locate Moon in the fixed sequence. For a Moon mahādaśā, convert 10 nominal years using the declared year-length convention. For a Moon antardaśā inside any parent period, multiply the parent duration by 10/120 and preserve the parent lord, timestamps, and rounding policy.
Required inputs
- Natal Moon Lahiri-sidereal nakṣatra and elapsed fraction
- Fixed nine-lord sequence
- Moon duration weight of 10/120
- Declared year length and timestamp rounding
Maha convention
Maha uses 365.2425 days per nominal year, computes the birth balance from the Moon’s solved ingress-to-egress time fraction, and stores UTC boundaries. The Moon label identifies a position in that chronology, not a generated interpretation.
Uncertainty and edge cases
Birth-time uncertainty, ayanāṁśa choice, Moon ephemeris, nakṣatra-boundary proximity, year length, and rounding can alter period boundaries. A natal Moon near a nakṣatra edge can also change the starting lord entirely.
How reports may use this reference
A report may state when the calculated Moon period starts and ends, its level, parent period, nominal duration, and method. Interpretive statements require source-bound daśā rules and practitioner review; none are inferred from the lord name here.
What this does not establish
A Moon period does not establish that a particular event, personality state, financial result, relationship change, or business outcome will occur.
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.