Mercury Mahadasha, Sun Antardasha (Budh–Surya)

The Sun antardasha is the fourth of the nine sub-periods inside the Mercury mahadasha. 17 × 6 ÷ 120 makes the Mercury–Sun 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.

The Sun’s turn in the Mercury mahadasha comes only after Mercury, Ketu and Venus have run, which takes 6 years 2 months 24 days. When the Mercury–Sun sub-period gives way to Mercury–Moon, 9 years 11 months of the Mercury mahadasha remains.

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

The Nine Pratyantardashas of Mercury–Sun

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

How Mercury and the Sun Stand to Each Other

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

Counted between the signs they own, Leo is the 3rd from Mercury’s Gemini and Leo is the 12th from Mercury’s Virgo. Whatever the ascendant, the houses Mercury rules and the houses the Sun rules sit at those same distances from each other in the chart, so the Mercury–Sun sub-period always joins lordships that far apart.

The Same Pair the Other Way Round: Sun–Mercury

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

What the Texts Assign to Mercury and the Sun

The karaka list the tables give Mercury, the mahadasha lord, is speech, writing, trade, accounts, mathematics, maternal uncles and students; for the Sun, the lord of the Mercury–Sun sub-period, it is father, government, authority, the soul (atma) and administration. Parashari practice reads the sub-period through the houses each of the two owns and occupies in the birth chart, and through where the Sun stands counted from Mercury there. None of that is a forecast, and this page makes none: without a chart, Mercury–Sun 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 Ashlesha, Jyeshtha or Revati opens life inside the Mercury mahadasha itself, part-way through, and whether the Mercury–Sun sub-period is still ahead depends on how far the Moon had gone into the nakshatra. For a birth in Krittika, Uttara Phalguni or Uttara Ashadha, the Sun mahadasha comes first, and the Mercury mahadasha is the seventh 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 सूर्य अंतर्दशा.