Uttara Ashadha is nakshatra number 21 of the 27 lunar mansions in Vedic astrology, spanning 266.67° of the zodiac in 13°20' steps. Its planetary lord is Sun and its presiding deity is Vishvedevas.
The Moon's position in Uttara Ashadha at birth shapes the Vimshottari Mahadasha sequence — a Uttara Ashadha birth begins life in the Sun 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 Uttara Ashadha is your janma nakshatra, and the Panchang to see exactly when the Moon transits Uttara Ashadha on any date.