The Garuda Purana
Describing the period for which a particular planet is supposed to have its influence on the native, Lord Vishnu told Shiva– ‘ Surya’s dasha continues for six years and brings turbulence, turmoil and agony to the concerned person. Moon’s dasha continues for fifteen years and is considered very auspicious as it brings happiness and prosperity. Mangal’s dasha is considered inauspicious and lasts for eight years. It brings sorrow and misfortune. Buddh’s dasha is auspicious and lasts for seventeen years. It brings all kinds of favorable results and is extremely rewarding in every respect. Shani’s dasha lasts for ten years and brings all kinds of inauspicious results to a man. Vrihaspati’s dasha continues for nineteen years and is extremely auspicious. Rahu’s dasha continues for twelve years and is inauspicious. Shukra’s dasha lasts for twenty years and is auspicious.’
NOTE — The period of years stated in the above mentioned Graha- dashas are at variance from those mentioned by sage Parashar, which is in practice nowadays.