Subject: Golf scopes, M19
The 5 x 20 golf scopes ....are being closed out, replaced by in infrared rangefinder type. They have several uses in binocular testing and adjustment, at virtual giveaway prices. Army-Henson setups in particular, but with angular measurement capability also. Ignore the "yards" , measure the reticle from the front with a surveying instrument or with a milscale equipped sight or binoc, and convert to degrees(if desired). I always seem to not have my calculations at hand.( I am at a library)
What is the story on M-19 "collimation"? Has somebody figured a way around the locked-in modular concept, with no adjustments Or, do they get a whole bunch of modules and just assemble? As you probably know, adhesive failure in the prism mounts caused the program to fail in the field. Ditto the (more primitive, non-modular) Katsuma (jb-7) Tasco, Baker, Swift, etc 7 x 50, and , to a lesser extent, 8 x 30. I could go on,but might get in trouble with ongoing relationships . Built-in failure probability of the brittle gray glue no doubt boosts future business, both civilian and military..( The M-19 was a different adhesive). M-19 is well documented in old SPIE journal articles and publications. The failures were not ever mentioned there, to my knowledge.
Subject: supply problems
About 25 years, ago, I bought a Mark 28 B&L in the box. It was marked 1942, and had a little handwritten tag on the glass, reading July, 1942. My father who was in the Navy from 1943 to 1946, served on the
gun crews aboard American merchant ships. Throughout the war, he used binoculars lent to the Navy by citizens. This would seem to mean that while my glass sat on a shelf somewhere, for years, sailors were using inferior optics. To put it another way, production outstripped the ability to supply those in need, another examp;le of the waste of war.
Subject: New large amateur astronomy binoculars
David Moorhouse; 16 Inch Binocular Telescope Page
Auckland, New Zealand
Subject: German 6x30 manufacturers during WWII:
A list of factories producing 6x30's. Expanded from a discussion on Deutsche Optik's page, where 3 letter codes from existing binoculars were listed. Correlations of codes with factories is from John Walter, German Military Letter Codes. Some of these, such as fzg or erv, are 'new to me'. Leidolf was included in the list of military manufacturers.
beh Leitz Wetzlar
bek Hensoldt Herborn
blc Zeiss Jena
bmj Hensoldt Wetzlar
bmk Srb & Stys, Prag
cad Kahles Wien