Ignatius
Putting the Red back into Redneck
Looking through the internet I have come across several old German naval binoculars from WW1 which have arcane formulae engraved on them.
These have the form E = n x G.
On one of those binoculars, a D.F. 7x50 from 1918 with a FOV of 128 m, n = 7.8 (coincidentally? 1000/128 = 7.8) and on the other one, a 1924 Leitz Aviosept 7x with a FOV of 105 m, n = 9.5 (coincidentally? 1000/105 = 9.5).
Neither of these binoculars has a reticle and therefore I take the formula to be a help for lookouts to determine distances to objects (the German for distance is Entfernung).
I tried using the known length of a warship in metres (filling the image of the binoculars for reference) for G (Grösse?) but that gave me a ridiculously close distance - well within range of naval artillery and almost dangerously close enough for a pie throwing contest.
My question is this: does anyone have any idea what the G in this formula is, and how the relationship of FOV to 1000 m distance might help estimating an actual distance.
These have the form E = n x G.
On one of those binoculars, a D.F. 7x50 from 1918 with a FOV of 128 m, n = 7.8 (coincidentally? 1000/128 = 7.8) and on the other one, a 1924 Leitz Aviosept 7x with a FOV of 105 m, n = 9.5 (coincidentally? 1000/105 = 9.5).
Neither of these binoculars has a reticle and therefore I take the formula to be a help for lookouts to determine distances to objects (the German for distance is Entfernung).
I tried using the known length of a warship in metres (filling the image of the binoculars for reference) for G (Grösse?) but that gave me a ridiculously close distance - well within range of naval artillery and almost dangerously close enough for a pie throwing contest.
My question is this: does anyone have any idea what the G in this formula is, and how the relationship of FOV to 1000 m distance might help estimating an actual distance.