Except for the two galaxies M81 and M82 too far north, all the 110 Messier objects are on the map. If you know how to
find a constellation in the sky, this map will show you what objects you can find inside that constellation.
Clic first on one of the four seasons to get a smaller map. Then you will choose a particular constellation, and you will get access to the celestial objects inside that constellation. The area of the map said to be "summer sky" is what you can see during summer between sunset and midnight.