Vimshottari dasha system

Vedic Astrology has a most brilliant system of timing when the effects of each planet will be felt, the dashas. Dashas are planetary cycles, which follow in a very specific order, with a very specific time span. There are various dasha systems, but we will consider here, the Vimshottari dasha system.The complete dasha cycle is 120 years. After a 120 years, the cycle repeats itself.
special case is Rahu and Ketu. Rahu is associated with the astroid belt which is located between Mars and Jupiter, and Ketu is placed opposite of Rahu in this cycle of 9.The Vimshottari dasha order is the same as the rulerships of the nakshatras. The 27 nakshatras are divided in three cycles of 9, and the nakshatras within each group are ruled by the 9 Grahas. The first Nakshatra is ruled by Ketu, and the other 8 rulers follow in the order of the Vimshottari dashas.The duration of the dashas is as follows: Ketu 7, Venus 20, Sun 6, Moon 10, Mars 7, Rahu 18, Jupiter 16. Saturn 19, Mercury 17. The dasha the person is born in, is determined by the ruler of the Moon's Nakshatra.