On a recent (first) visit to the Channel Islands, hubby & I visited an occupation memorial museum in an old gun bunker. Amongst a display of ex-Lufwaffe memorabilia was a display of nav plotting tools, most of which I could recognise from my old PPL training (plus a bit of imagination), but this one has me stumped. Apologies for quality, I've over-enhanced it from a dull photo photo.
Thanks
MB