Ardra is nakshatra number 6 of the 27 lunar mansions in Vedic astrology, spanning 66.67° of the zodiac in 13°20' steps. Its planetary lord is Rahu and its presiding deity is Rudra.
The Moon's position in Ardra at birth shapes the Vimshottari Mahadasha sequence — a Ardra birth begins life in the Rahu 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 Ardra is your janma nakshatra, and the Panchang to see exactly when the Moon transits Ardra on any date.