In Vedic astrology, a planet’s orbit around the zodiac is known as its “revolution.” The time taken for a planet to complete one revolution around the zodiac is called its planetary period (or Mahadasha). Here’s a summary of the approximate planetary periods in Vedic astrology:

1. Ketu: Due to its elliptical orbit, Ketu’s revolution takes around 3.44 years. However, as Ketu’s period isn’t used in the Navamsa (divisional chart), it’s not given a precise planetary period.
2. Rahu: Rahu’s revolution takes approximately 3.44 years; like Ketu, Rahu also doesn’t have a specific planetary period in the Navamsa chart.
3. Jupiter (Guru): Jupiter’s revolution takes about 11.6 years to complete one orbit. In Vedic astrology, Jupiter has the longest planetary period, and its influence is profound during the juvenile phase of an individual’s life.
4. Saturn (Shani): Saturn takes around 29.5 years to complete one revolution. Its influence is strong during the middle age and holds significant importance in one’s life.
5. Mercury (Budh): Mercury’s revolution takes approximately 15 months. Its planetary period plays a vital role during the first half of one’s life.

For the remaining planets – Sun (Surya), Moon (Chandra), Mars (Mangal), and Venus (Shukra):

1. Sun: As the mean distance between the Earth and the Sun (1 AU) is roughly equal to an Earth-year, Sun’s planetary period is considered to be one Earth-year (365.25 days).
2. Moon: Moon’s revolution around the zodiac takes about 27.3 days. Its relative speed is greater than other planets, making its planetary period approximately 2.15 years.
3. Mars: Mars takes about 687 Earth-days (or approximately 2 Earth-years) to complete one orbit. Its planetary period is around 2 years.
4. Venus: Venus takes around 224.7 Earth-days (or approximately 0.62 Earth-years) to complete one revolution. Its planetary period is approximately 1.6 years.

These planetary periods are also known as Mahadasha periods and are considered vital in Vedic astrology. Astrologers often use these periods to understand an individual’s life events, tendencies, and key life lessons. These are approximate durations and may vary slightly based on the specific astrological calculations. A professional astrologer can provide a more accurate assessment based on your unique birth chart.