Binoculars Carl Zeiss Jena Turex 6x21

Magnification: 6x
Aperture (objective diameter): 21 mm
Field of view: 8.5°
Exit pupil diameter: 3.5 mm
Visible field of view (eyepiece FOV): 50°
The closest focusing distance: 2 m
Width: 9.4 cm
Height: 8.7 cm
Weight: 266 g
Production date: 1922.

   In 1914, compact binoculars Carl Zeiss Turex 6x and Carl Zeiss Turexem 6x (with central focusing) appeared in the T180 Carl Zeiss Jena catalog. Structurally, these two binoculars are similar to the Turol 4x and Turolem 4x models, but they have a magnification of 6x and a lens diameter of 21 mm. Turex 6x and Turexem 6x are positioned in the catalog as lightweight and compact binoculars for travel and tourism.
    However, there is information that the first instances of Turex 6x appeared in 1913. This model was produced until about the mid-20s. Unlike Turol 4x, Turex 6x has no military counterpart.
   Turex 6x (like Turol 4x) had the same distance between the lenses and the eyepieces (base), which affected the binocular’s plasticity negatively. It was a rather unusual design solution for Carl Zeiss binoculars of that time, since there even was a condition of Carl Zeiss patent in the period from 1896 to 1908, according to which other manufacturers of prismatic binoculars were required to produce their models with the same distance between the lenses and the eyepieces. This design decision may have been dictated by the desire to reduce the size and weight of these devices.
   Several modifications of this model with minor design differences are known for the time being:
   - with rounded objective covers with the grooves to minimize stray light and with the central hinge clamp (lock) (first version ,released for a short time from 1913 to 1914)
   - with rounded objective covers without the grooves to minimize stray light and with the central hinge clamp (lock). Changed the shape of the eyecups of binoculars. (released from 1914 with a break till 1920/21)
   - with rounded objective caps without the grooves to minimize stray light and without the central hinge clamp (lock) (released from 1920/21 to the mid-20s)
   This device belongs to the third design version. It has the eyepieces with base diameter equal to 20.6 mm and the upper prism cover width equal to 38.5 mm (see photo). The eyepieces’ front lens diameter is equal to 10.5 mm. The eyepieces have a diopter scale and a diagonal knurling. The binocular’s body height (including the upper prism cover) is equal to 56 mm; this value is equal to 39.5 mm without the lens barrel. The prism covers are pressed to the binocular’s body with the help of lens covers and the “skirts” at the eyepieces’ base. The prism covers are attached on the side to the housing with the help of one screw.
   There are inscriptions “Carl Zeiss Jenna” on the left prism cover. There is also an inscription “Turex 1154296 6x” on the right prism cover.  The inscription is made in block letters on the background of Carl Zeiss Tessar photo lens schematic image.
   The binocular’s coffer has features peculiar to that period (see Hans T. Seeger. Zeiss Handfernlaser 1919-1946, Modelle-Merkmale-Mythos, pp. 607-627): specific rivets, an embossed “Carl Zeiss Jenna” logo.
   The serial number of the binoculars is "1154296", it was made in 1922 in a batch of 300 pieces.  
   The binocular’s model with central focusing, namely Turexem 6x, was released in 1914.