Why when looking through a telescope at an object the RA and the DEC do not change?

I get really confused about this because for example if you look at the Orion Nebula for example. At 9:00pm right now it is below the horizon in PA where I live. If you go out around 2:00 am you will be able to observe it. So how can the RA and the DEC still be the same coordinates if the item is constantly moving. Can anyone out there explain to me how this works?