Ketu Mahadasha, Ketu Antardasha (Ketu–Ketu)

The Ketu antardasha is the opening sub-period of the Ketu mahadasha: the nine sub-periods always begin with the mahadasha’s own lord, so Ketu runs inside Ketu before any other graha takes a turn. 7 × 7 ÷ 120 makes the Ketu–Ketu sub-period 4 months 27 days on the classical year of twelve thirty-day months, which is how the texts state it, or 149 days on the solar year of 365.2425 days that the dasha calculator uses.

Coming first, the Ketu–Ketu sub-period opens on the day the Ketu mahadasha does, and when it ends 6 years 7 months 3 days of the Ketu mahadasha is still to run, through Venus, the Sun, the Moon, Mars, Rahu, Jupiter, Saturn and Mercury in that order.

Ketu’s 7 years make every Ketu antardasha 7/120 of the mahadasha containing it, so inside its own mahadasha the Ketu–Ketu sub-period is the seventh-longest of the nine, level with Ketu–Mars, because Mars and Ketu each run 7 years as mahadashas.

The Nine Pratyantardashas of Ketu–Ketu

A pratyantardasha of Ketu–Ketu is 7 × 7 × its own lord’s years ÷ 14,400, and the nine run in cycle order starting from Ketu. Venus’s is the longest inside Ketu–Ketu at 25 days and the Sun’s the shortest at 7 days, on the classical year and rounded to the day.

Ketu Inside Its Own Mahadasha

With one lord, the Ketu–Ketu sub-period has no friendship to read and no sign-to-sign distance to count. Ketu owns no sign in the standard scheme, and its exaltation is recorded as “Scorpio by the most common reckoning; Sagittarius in others”, so the Ketu–Ketu sub-period is read through the lord of the sign Ketu occupies at birth.

Every mahadasha opens with its own lord, so the cycle holds nine such sub-periods, each its lord’s years squared and divided by 120. At 4 months 27 days (7 × 7 ÷ 120 years), Ketu–Ketu is the seventh-longest of the nine, level with Mars–Mars; the longest, Venus–Venus, runs 3 years 4 months.

What the Texts Assign to Ketu

The karaka list the tables give Ketu is moksha, past-life skill, renunciation, occult knowledge and flags and banners. In the Ketu–Ketu sub-period that list is the only one in play, read throughthe house Ketu occupies in the birth chart and the lord of the sign it sits in, since Ketu owns no sign. None of that is a forecast, and this page makes none: without a chart, Ketu–Ketu is a length and a position, and the 4 months 27 days above is the whole of what can be said about it in general.

A birth with the Moon in Ashwini, Magha or Mula opens life inside the Ketu mahadasha itself, part-way through, so the Ketu–Ketu sub-period may already be over at birth.

The Other Sub-Periods of the Ketu Mahadasha

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