Purva Phalguni is nakshatra number 11 of the 27 lunar mansions in Vedic astrology, spanning 133.33° of the zodiac in 13°20' steps. Its planetary lord is Venus and its presiding deity is Bhaga.
The Moon's position in Purva Phalguni at birth shapes the Vimshottari Mahadasha sequence — a Purva Phalguni birth begins life in the Venus mahadasha, with the balance of that period decided by how far the Moon had travelled through the nakshatra.
Use the free Kundli generator to find whether Purva Phalguni is your janma nakshatra, and the Panchang to see exactly when the Moon transits Purva Phalguni on any date.