Rohini is nakshatra number 4 of the 27 lunar mansions in Vedic astrology, spanning 40.00° of the zodiac in 13°20' steps. Its planetary lord is Moon and its presiding deity is Brahma.
The Moon's position in Rohini at birth shapes the Vimshottari Mahadasha sequence — a Rohini birth begins life in the Moon 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 Rohini is your janma nakshatra, and the Panchang to see exactly when the Moon transits Rohini on any date.