Messier objects are a mixed population that includes galaxies, gas clouds (or nebulae) and star clusters. Following this use case you will explore some of the most representative objects of the Messier catalog. You will retrieve and visualize them with Aladin and Stellarium, an application that will let you check where to look for objects visible from your location. Contact: G. Iafrate, iafrate at oats.inaf.it en (master): 2014-01-29 it: 2014-01-29