Maghé Sankranti is the first day of the month of Magh marking the entering of Sun to Makar or the Capricornus constellation. The sun will remain in this constellation for the whole month of Magh. The first day, Maghé Sankranti, is celebrated with a feast of laddus of til and chaku, ghee, chaku and beaten rice. On the day we worship Lord Vishnu- the Preserver of the Universe to thank for the return of warm season. People around the Hind sub-continent take an early morning bath in holy rivers, visit the shrines of Vishnu and read Bhagavad Gita, a book of stupendous philosophy, that contains sacred instructions given by Krishna to Arjuna during the war of Mahabharata.
The actual date for the entering of Sun accepted by modern astronomers is, however, 6th of Magh. The difference is due to different ways of dividing the sky used by modern astronomers and vedic astronomers. Maghé Sankranti actually marked the winter solstice when the calendar was first introduced. Now, due to the precession of equinoxes this occurs on Poush 7.