NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Art Leung
Date: 2025 May 12, 07:40 -0700
Dan, my Polhemus computer has 7 disks.
For practice and to share, I plotted my most recent 3-star series on the back of the Polhemus. First picture has the disk mounted on the grid - the second picture has it off the grid to make things easier to see. This was pre-planned and reduced using the Air Almanac, Pub249v1, and the Polhemus computer (with airspeed = 0 so no motion of the observer). I shot this with a Kollsman periscopic bubble sextant in a field surrounded by trees.
I used a 2x scale on the plot to make things a little easier for you to see. I used the Table-5 (Pub249v1 Precession and Nutation Correction) correction on the assumed position (AP is the tip of the chevron, the Table-5 correction is the dot next to it).
This fix missed my actual by no more than 0.5nm on both my paper plot (NA, Pub229) and Polhemus plot.
