Through the ceiling catalogs are lists of deep sky
objects that occupy a fixed position in the sky. They are very useful for
amateur astronomers, because they collect the main galaxies, nebulae and star
clusters that can be seen with a telescope medium.
In the best known are: Messier catalog: the most famous and the first to be published. He
was drafted by the French astronomer Charles Messier in 1769. It brings
together 110 objects numbered M1 to M110, in the order in which the Messier
discovered while watching the skies for comets.
