Sun Mahadasha, Mercury Antardasha (Surya–Budh)

The Mercury antardasha is the seventh of the nine sub-periods inside the Sun mahadasha. 6 × 17 ÷ 120 makes the Sun–Mercury sub-period 10 months 6 days on the classical year of twelve thirty-day months, which is how the texts state it, or 310 days on the solar year of 365.2425 days that the dasha calculator uses.

Mercury’s turn in the Sun mahadasha comes only after the Sun, the Moon, Mars, Rahu, Jupiter and Saturn have run, which takes 3 years 9 months 18 days. When the Sun–Mercury sub-period gives way to Sun–Ketu, 1 year 4 months 6 days of the Sun mahadasha remains.

Mercury’s 17 years make every Mercury antardasha 17/120 of the mahadasha containing it, so inside the Sun’s 6 years the Sun–Mercury sub-period is the fourth-longest of the nine.

The Nine Pratyantardashas of Sun–Mercury

A pratyantardasha of Sun–Mercury is 6 × 17 × its own lord’s years ÷ 14,400, and the nine run in cycle order starting from Mercury. Venus’s is the longest inside Sun–Mercury at 51 days and the Sun’s the shortest at 15 days, on the classical year and rounded to the day.

How the Sun and Mercury Stand to Each Other

On the natural friendship table, the Sun counts Mercury neutral while Mercury counts the Sun a friend. The table is not symmetric, so the Sun–Mercury relationship has to be quoted in both directions, as it is here, rather than as one word.

Counted between the signs they own, Gemini is the 11th from the Sun’s Leo and Virgo is the 2nd from the Sun’s Leo. Whatever the ascendant, the houses the Sun rules and the houses Mercury rules sit at those same distances from each other in the chart, so the Sun–Mercury sub-period always joins lordships that far apart.

The Same Pair the Other Way Round: Mercury–Sun

6 × 17 equals 17 × 6, so the Sun antardasha of the Mercury mahadasha is exactly as long as Sun–Mercury: 10 months 6 days. Nothing else about Mercury–Sun matches. It is the fourth sub-period of Mercury’s 17 years rather than the seventh of the Sun’s 6; it opens after 6 years 2 months 24 days of the Mercury mahadasha, against 3 years 9 months 18 days here; and its pratyantars start from the Sun instead of Mercury.

What the Texts Assign to the Sun and Mercury

The karaka list the tables give the Sun, the mahadasha lord, is father, government, authority, the soul (atma) and administration; for Mercury, the lord of the Sun–Mercury sub-period, it is speech, writing, trade, accounts, mathematics, maternal uncles and students. Parashari practice reads the sub-period through the houses each of the two owns and occupies in the birth chart, and through where Mercury stands counted from the Sun there. None of that is a forecast, and this page makes none: without a chart, Sun–Mercury is a length and a position, and the 10 months 6 days above is the whole of what can be said about it in general.

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

The Other Sub-Periods of the Sun Mahadasha

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