Moving constellations

We usually think that stars are fixed in the sky and that their mutual positions do not change in time. Ancient civilizations built their religious and philosophical systems on this empirical evidence. However, we now know that this is not true; stars have proper motions, meaning that their position changes with time. The reasons why the measurements of the proper motions were lagging is twofold: stars move on a time scale of tens of thousands of years, too long when compared with human lifetime, and the measurement of the proper motion requires very precise and accurate space observing facilities. This activity intends to show practically this motion in action, using free software, satellite data and other accessible tools that give evidence of how constellations shapes evolve in time.