Binoculars Carl Zeiss Jena Turact 8x

Magnification: 8x
Aperture (objective diameter): 24 mm
Field of view: 6.3°
Exit pupil diameter: 3 mm
Visible field of view (eyepiece FOV): 50°
The closest focusing distance: 6.5 m
Width: 15.7 cm
Height: 9.8 cm
Weight: 455 g
Production date: 1913.

   In 1912, a very successful Telact 8x model was replaced by Turact 8x. Carl Zeiss decided to make a cheaper binocular, so he simplified the Turact design. The new binocular turned out to be much smaller and lighter, and respectively, more convenient in application. However, its field of view was decreased (from 6.6° to 6.3°) and the aberrations increased. Both binoculars were produced in parallel approximately from 1912 to 1915, and Turact production stopped around the end of 1920s.
   Turact is a “civilian” model; this fact is proved by the central hinge fixture’s (clamp’s) small diameter (see photo), which has a hole for a knob (included to binoculars delivery kit), with the help of which the hinge could have been finally fixed depending on the observer’s interpupillary distance. The interpupillary distances scale is indicated on the upper hinge disk. Similar military models are labeled as D.F.8x, D.F.8x24 and D.F.95 n/A.
   Turact was produced with various design changes in 2 versions:
   1st version: with the two-ring type lens frames (starting from 1912 and up to the mid of 1913); and with the eyepieces carcass having the “diagonal” knurling (see photo)
   2nd version: with rounded objective covers (starting from 1913 and up to the end of the 20s);
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  This device belongs to first, rather rare design version.
   The binocular has eyepieces with base diameter equal to 20.5 mm and upper prism cover width is equal to 46 mm (see photo). The eyepieces’ front lens diameter is 10.5 mm. The eyepieces have a diopter scale and the diagonal knurling. The binocular’s body height (including upper prism cover) is equal to 68.5 mm; the height without lens frame is 52 mm. Prism covers are attached to the housing with the help of three screws.
   There are inscriptions “Carl Zeiss Jenna” on the left prism cover. There is also an inscription “Turact 349188 8x” on the right prism cover. The inscription is encrusted with the help of silver alloy and is made in block letters against the background of Carl Zeiss Tessar photo lens schematic image.
   The binocular’s coffer has peculiarities specific to that period (see Hans T.Seeger. Zeiss Handfernlaser 1919-1946, Modelle-Merkmale-Mythos, pp. 607-627), namely, the design of self-tightening side belt fasteners, carrying handle on the top cover, the top cover fastening to coffer’s case, specific rivets (see photo). A knob for adjusting the locking handle is included into the binocular’s delivery kit. The coffer’s upper cover is of the “seamless” design.
   The binocular’s serial number is “349188” and it was released as a 200 pieces batch in 1913. 
   The Turact’s "predecessor", namely the Telact model can be checked by the following link: https://binocollection.com/catalog/binocular-carl-zeiss-jena-telact-8x-1.html
   The Turactem 8x, the binocular’s model with central focusing, was released in 1914.