How to Make a Mortar a Thousand Meters Away

The Norden bomb site is inside the bomber and there's a human that looks through it. It had to be protected so what I'm saying is where is it located on the actual plane and what steps were taken to to keep it functional. You took my question to mean like what geographical location is this site where bombing occurred. If there was a book on the Norden bomb sites I would read itThere's got to be a book. Was it an analog computer format or did you do math on paper in the early days with this? Uh trial and error...I'd see where the first one hit and then I'd try to adjust.