Mahabharata, Book 13, Section CXअनुशासनपर्व

"Vaisampayana said, 'Approaching the Kuru grandsire, venerable in years, viz., Bhishma, who was then lying on his bed of arrows, Yudhishthira possessed of great wisdom put the following question.'

"'Yudhishthira said, "How, O grandsire, does one acquire beauty of form and prosperity and agreeableness of disposition? How, indeed, does one become possessed of religious merit and wealth and pleasure? How does one become endued with happiness?"

"'Bhishma said, "In the month of Margasirsha, when the moon comes in conjunction with the asterism called Mula, when his two feet are united with that very asterism, O king, when Rohini is in his calf, when his knee-joints are in Aswini, and his shins are in the two Ashadhas, when Phalguni makes his anus, and Krittika his waist, when his navel is in Bhadrapada, his ocular region in Revati, and his back on the Dhanishthas, when Anuradha makes his belly, when with his two arms he reaches the Visakhas, when his two hands are indicated by Hasta, when Punarvasu, O king, makes his fingers, Aslesha his nails, when Jyeshtha is known for his neck, when by Sravana is pointed out his ears, and his mouth by Pushya, when Swati is said to constitute his teeth and lips, when Satabhisha is his smile and Magha his nose, when Mrigasiras is known to be in his eye, and Chitra in his forehead, when his head is in Bharani, when Ardra constitutes his hair, O king, the vow called Chandravrata should be commenced. Upon the completion of that vow, gift of ghee should be made unto Brahmanas conversant with the Vedas. As the fruit of that vow, one becomes possessed about knowledge. Indeed, one becomes, in consequence of such a vow, as full (of every blessed attribute) as the moon himself when he is at full."'"