A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Gary LaPook
Date: 2021 Jul 14, 21:56 -0700
It's a Fairchild A-10. You push the button each time when you have the body centered in the bubble and the button moves a pencil that makes a mark on the white disk. At the end of you shooting you estimate the median of all the pencil marks and line that up with the pencil tip which then causes the counter to show the meidan altitude of the series of shots.
This manual is for the A-10a which added an electric timer that makes marks on the disk every second that you depress the trigger. The median of the shots is found the same way as with the original A-10.