Telescope Reviews: A Navy optical book, including binoculars repair

Cory,
graphs, pictures, diagrams and trig are mine. I just thought that some explanation about this recurrent question “equilateral or isosceles” (recurrent here at CN) could have been interesting if not for everybody at least for members involved in binoculars overhauling. To explain that, I used part of an appendix of the text on collimation prepared for the course I gave here in Italy two years ago. This theme was in an appendix exactly because it was not so vital and could distract from the main theme (collimation procedures). So I am far to think that during the collimation process one should dissert on how much equilateral is the triangle to be constructed.
Nevertheless, I find interesting each and every theme related to binoculars production and overhauling. If I had been Joe Anyone and had been so lucky to learn from a very experienced teacher as you are and to start practising with a collimator, probably I would have found less need of asking myself so many questions about overhauling and collimation. But many years ago, when I was Claudio Anyone, I started working in a shop where binoculars repair was considered less remunerative, thus less interesting, than repairing cameras. They showed me a bunch of dusty binoculars and told me “fix them please”. After a few binoculars collimated for my IPD, a customer with a quite different IPD objected that his binocular was still not collimated. I started asking myself how this could happen and with time I arrived to understand the importance of the hinge and built my first (and still working) collimating device for binoculars. Could I have done this if I hadn’t been curious to know every aspect on binoculars?
Members who would like to restore and collimate binoculars of their collection (at least those binoculars that don’t worth a professional repair) are probably interested in understanding collimation as deeply as to be able to design and build a collimating device.
Now, very seriously: I think that here there is half a dozen people which personal experience and knowledge on these themes are precious for me, and I think that my contribution is of some value for them. I consider that there should be a common will to avoid that our knowledge gets lost. But instead of this aim, I see that very often there are only useless controversies that muddle the other members and take them away from these themes. In the last years my presence at CN has been seesawing because of this polemic spirit that is distant from my feeling and that frankly should stay far from discussions on technical themes.
Claudio