Nothing is the observer but there is observing. One must practice just seeing what arises and falls naturally without words and concepts that we use to make a different reality. Conceptual reality is human made as opposed to Ultimately reality that just is what it is, moment by moment, in our experiential awareness.

If you program computers perhaps this will help: 

Conceptual reality is to Ultimate reality like
Ruby language is to machine language. 

We cannot find a self when we see things as they are. As a rule of thumb, everything we experience is empty of self. Everything. Even the apparent observer or watcher. 
 
Not self simply shows us that we are empty of self as the trees and ponds and lakes obviously are empty of self too. To see anatta is to see yourself as just a bunch of impersonal processes.-Metta