The paper is proposing several examples of the use of Stellarium, an open source free software planetarium, for simulating the astronomical landscapes of the ancient stargazers. Here we will focus on the motion of the stars, in particular with respect to the precession of Equinoxes. Usually, we consider that this precession was discovered by Hipparchus of Nicaea (c. 190 – c. 120 BC), Greek astronomer and mathematician, who measured it comparing the positions of the stars that he observed to the data recorded a hundred of years before. In fact, Hipparchus gave us the first historical record of the precession but probably he was not the first to observe this motion of the heaven of the fixed stars. We can argue this possibility from the simulation of the sky seen by the ancient stargazers.