Hi Sebastian and welcome to IIS


8"dob....good buy
The list of objects you can see with an 8" telescope of any sort is almost endless. If you want to have a good look at nebulae and such things, grab yourself a UHC filter. That will block the light from streetlights and such and enhance the details in the objects. But objects like M42 (Orion Nebula) and NGC2070 (Tarantula Nebula, in the LMC), M1 (Crab Nebula, in Taurus), Rosette Nebula in Monoceros (associated with open cluster NGC2244), the Cone and Fox fur Nebulae plus the Christmas Tree Cluster (NGC2264, in the same constellation as the Rosette), M45 (the Pleaides, in Taurus...although better in binoculars), the Hyades (the horns of Taurus), the Beehive Cluster (M44) in Cancer and many many many more.
The best thing to do is go and download a program like
Stellarium, which is a planetarium program you can use to see what's up in the sky each night and to plan your observations.
Also, join your local Astronomical Society/Club and go to as many of their nights as you can. That's one of the ways to learn quickly and make new friends

Hope that helps
