Tula lagna · vimshottari
The Mercury Mahadasha for Libra Ascendant
17 years · Mercury rules the 9th and 12th
The Parashari way to read a mahadasha for a given ascendant starts with the houses its lord holds. For Libra ascendant Mercury rules the 9th (Gemini) and the 12th (Virgo), so for Libra the 17-year Mercury mahadasha carries both a trikona house and a dusthana house.
Counted from Libra, Mercury is exalted in the 12th (Virgo) and debilitated in the 6th (Pisces). Venus, Libra’s lagna lord, and Mercury count each other a friend. Mercury’s own nakshatras fall in Ashlesha (the 10th), Jyeshtha (the 2nd) and Revati (the 6th) for Libra ascendant, which is where a birth that opens in the Mercury mahadasha has its Moon.
The Nine Sub-Periods, by Lordship for Libra
| # | Antardasha | Length (classical) | Its lord rules, for Libra |
|---|---|---|---|
| 1 | Mercury–Mercury | 2 years 4 months 27 days | the 9th and the 12th |
| 2 | Mercury–Ketu | 11 months 27 days | no house |
| 3 | Mercury–Venus | 2 years 10 months | the 1st and the 8th |
| 4 | Mercury–Sun | 10 months 6 days | the 11th |
| 5 | Mercury–Moon | 1 year 5 months | the 10th |
| 6 | Mercury–Mars | 11 months 27 days | the 2nd and the 7th |
| 7 | Mercury–Rahu | 2 years 6 months 18 days | no house |
| 8 | Mercury–Jupiter | 2 years 3 months 6 days | the 3rd and the 6th |
| 9 | Mercury–Saturn | 2 years 8 months 9 days | the 4th and the 5th |
For Libra ascendant, three of the Mercury mahadasha’s sub-periods belong to lords of a dusthana (the 6th, 8th or 12th): Mercury–Mercury, Mercury–Venus and Mercury–Jupiter, and two to lords of a trikona other than the 1st: Mercury–Mercury and Mercury–Saturn. The sub-period of Venus, Libra’s lagna lord, is Mercury–Venus, the third of nine, 2 years 10 months long. Counted in time, sub-periods whose lords hold a dusthana for Libra take 7 years 6 months 3 days (44%) of the Mercury mahadasha’s 17 years, and those whose lords hold a trikona other than the 1st take 5 years 1 month 6 days (30%); a lord holding both is counted in both. In the Mercury mahadasha for Libra, the Rahu and Ketu sub-periods are read through their dispositors in the chart, since neither node rules a house.
For a Libra-rising chart this is the frame of the Mercury mahadasha, not a forecast: where Mercury and each sub-period lord actually sit, and their dignity there, decide what it comes to, and this page cannot know either.
Related
For Libra or any other ascendant, the Mercury mahadasha’s sub-period arithmetic, with the nine pratyantars of each, is on the Mercury mahadasha table; the Libra chart house by house on the Libra ascendant page. How the Mercury mahadasha is read in general is in our Mercury mahadasha article, and the system in Vimshottari dasha explained.