8x20 B.U.1905 artillery prism binoculars from Fochtlander and Sons

Since 1899, the RIA Main Artillery Directorate, in connection with the conversion of field artillery to new rapid-firing 3-inch guns and the need to equip batteries with such guns with optical devices with sufficiently large magnification and field of view, conducted numerous tests of prism binoculars of various designs and manufacturers. In 1901, according to the auction results, several batches of Hertz binoculars with 9X magnification were purchased for such batteries, but three years later it was decided to continue to purchase binoculars with 8X magnification, since all the most famous companies made binoculars with such magnification, and only Hertz with 9x magnification. Technical specifications were developed for receiving prismatic GAU binoculars, and binoculars manufactured in accordance with such specifications were marked with the symbol "B.U." with the year. In 1904, 1,500 8x20 binoculars were ordered by Hertz and 750 by the FOS plant (at his urgent request, in order to establish the production of prism binoculars in Russia). However, based on the results of all the field tests, the GAU was unable to choose the single best model and supplier of binoculars for field artillery, so in 1905, 1,000 8x20 binoculars were ordered from five companies at once — Zeiss, Hertz, Kraus, FOS and Based on the test results of all these binoculars in the military and subsequent reviews, Fochtlander finally resolved the issue of a single model of binoculars for field artillery. Fochtlander binoculars have been tested by the GAU since 1902, both on At the Main artillery range, and in The electrical laboratory of the Gun Factory. It was recognized that they were somewhat inferior to Hertz binoculars in terms of manufacturing strength and field of view, but slightly superior in image clarity, so Fochtlander was allowed to bid for the supply of 8x20 binoculars by AK Magazine No. 495 dated July 6, 1904. However, according to the results of tests in the army, Zeiss and Hertz binoculars were recognized as the best, and a batch of 1,000 binoculars turned out to be the only one supplied to the field artillery of the Russian army for the Fochtlander company. The model was also used as a sample when the GAU ordered the first batch of 315 prismatic binoculars for RIA machine-gun teams in 1905.