The easiest way to reach Arcetri's Observatory is by taxi, which takes about 10 minutes in normal traffic conditions. If you prefer to go by bus you must move from the station square to Unità's Square, go on for about a hundred metres and then catch the bus number 11 direction Due Strade (Two Streets) and get off at Via del Gelsomino at the first bus stop.
From here you must go on foot along V.le del Poggio Imperiale. At the end of the street, you have to turn left at the entrance gate (about 5 minutes). From the entrance gate it will take about ten minutes to reach the Observatory.