Mercury Mahadasha, Rahu Antardasha (Budh–Rahu)

The Rahu antardasha is the seventh of the nine sub-periods inside the Mercury mahadasha. 17 × 18 ÷ 120 makes the Mercury–Rahu sub-period 2 years 6 months 18 days on the classical year of twelve thirty-day months, which is how the texts state it, or 931 days on the solar year of 365.2425 days that the dasha calculator uses.

Rahu’s turn in the Mercury mahadasha comes only after Mercury, Ketu, Venus, the Sun, the Moon and Mars have run, which takes 9 years 5 months 27 days. When the Mercury–Rahu sub-period gives way to Mercury–Jupiter, 4 years 11 months 15 days of the Mercury mahadasha remains.

Rahu’s 18 years make every Rahu antardasha 18/120 of the mahadasha containing it, so inside Mercury’s 17 years the Mercury–Rahu sub-period is the third-longest of the nine.

The Nine Pratyantardashas of Mercury–Rahu

A pratyantardasha of Mercury–Rahu is 17 × 18 × its own lord’s years ÷ 14,400, and the nine run in cycle order starting from Rahu. Venus’s is the longest inside Mercury–Rahu at 153 days and the Sun’s the shortest at 46 days, on the classical year and rounded to the day.

How Mercury and Rahu Stand to Each Other

Rahu’s row in the friendship lists counts Mercury a friend. Mercury’s row names no node, so the other direction of the Mercury–Rahu relationship has no entry, and this page does not supply one. The nodes have no row in the seven-graha table that kundli matching uses; the node’s own entry is the one printed on its planet page.

Rahu owns no sign in the standard scheme, so the Mercury–Rahu sub-period has no fixed distance between lordships. What stands in for it is the node’s dispositor — the lord of the sign Rahu occupies at birth — which differs from chart to chart.

The Same Pair the Other Way Round: Rahu–Mercury

17 × 18 equals 18 × 17, so the Mercury antardasha of the Rahu mahadasha is exactly as long as Mercury–Rahu: 2 years 6 months 18 days. Nothing else about Rahu–Mercury matches. It is the fourth sub-period of Rahu’s 18 years rather than the seventh of Mercury’s 17; it opens after 7 years 11 months 12 days of the Rahu mahadasha, against 9 years 5 months 27 days here; and its pratyantars start from Mercury instead of Rahu.

What the Texts Assign to Mercury and Rahu

The karaka list the tables give Mercury, the mahadasha lord, is speech, writing, trade, accounts, mathematics, maternal uncles and students; for Rahu, the lord of the Mercury–Rahu sub-period, it is foreign lands and foreigners, technology, aviation and politics. Parashari practice reads the sub-period through the houses each of the two owns and occupies in the birth chart (for Rahu, which owns none, the house it occupies and the lord of its sign), and through where Rahu stands counted from Mercury there. None of that is a forecast, and this page makes none: without a chart, Mercury–Rahu is a length and a position, and the 2 years 6 months 18 days above is the whole of what can be said about it in general.

A birth with the Moon in Ashlesha, Jyeshtha or Revati opens life inside the Mercury mahadasha itself, part-way through, and whether the Mercury–Rahu sub-period is still ahead depends on how far the Moon had gone into the nakshatra. For a birth in Ardra, Swati or Shatabhisha, the Rahu mahadasha comes first, and the Mercury mahadasha is the fourth in that sequence.

The Other Sub-Periods of the Mercury Mahadasha

The full table for the Mercury mahadasha, with where each sub-period opens and closes, is on the Mercury mahadasha page. How the Mercury mahadasha is read as a whole is in our Mercury mahadasha article, and the system itself in Vimshottari dasha explained. This page in Hindi: बुध महादशा में राहु अंतर्दशा.