A planet gets power based on the sign it sits. These planets shower either benefic result or malefic result to the native. But when does these planets gives those results to the native? How do we know that a particular period is good or bad for particular person?
There are different methods to time the effect of planets. The most accurate and widely used one is Vimsoththri dasa given by Sage Parashara. Vimsoththri means 120 in Sanskrit. This dasa system contains 120 years. Each planet has certain number of years. Each totals to 120 years.
Each of these dasa is further divided into 9 parts each ruled by nine planets. This is called ‘Pukthi’.
Each pukthi is again divided into 9 parts each ruled by nine planets. This is called ‘Anthra’.
It is divided into some more divisions. But for now it is sufficient if we know Dasa, Pukthi and Anthra.
These dasas will continue as per the order given above. Note that not every one’s dasa will start with Ketu dasa. It depends on the birth star/nakshatra. If the birth nakshatra is either of Ketu’s nakshatra then the first dasa will be Ketu dasa.
For example, if some one’s birth nakshatra/star is pushya/poosam, this nakshatra is owned by Saturn. Then the first dasa would be Saturn. Based on the quarter/paadha of the nakshatra, the remaining Saturn dasa will be determined.
Suppose, if the birth star is pushya/poosam 3rd paadha /quarter, then half of the star is passed. So only half of Saturn dasa will be remaining. From the age to 10 Mercury dasa(as it is the next dasa in above table) will start for that native for 17 years. After Mercury dasa, it will continue as Ketu dasa, Venus dasa, Sun data and so on.