Vimshottari Dasha Explained — Mahadasha, Antardasha, Pratyantardasha
The 120-year planetary period system used to time life events, computed from the Moon's natal nakshatra.
The 120-year cycle
Vimshottari divides 120 years among nine grahas: Ketu 7, Venus 20, Sun 6, Moon 10, Mars 7, Rahu 18, Jupiter 16, Saturn 19, Mercury 17. The cycle starts at birth from the lord of the Moon's nakshatra, for the balance of that nakshatra's span remaining at birth.
Three tiers of timing
A Mahadasha (major period) is divided proportionally into Antardashas (sub-periods), and each Antardasha further into Pratyantardashas. CosmicTantra computes all three tiers from the exact natal Moon longitude — the same dates must reproduce for identical input (our calculation invariants enforce this).
What a dasha reading is and is not
Dasha is timing context: which planetary flavor colours a period. It does not by itself predict events — interpretation requires the chart's strengths, transits and the practitioner's judgement. This is exactly why our reports separate the deterministic calculation from the human interpretation.