There is a certain treatment in Vedic astrology to see the Mahadasha period of time. In line with it, 3 Nakshatras are proportioned out to every World, which makes the amount of Nakshatras count to 27 for all of the 9 planets. So, the Mahadasha of any planet is determined https://www.youtube.com/shorts/oUsNAkX7h9w