U-Boot Zielfernrohr Carl Zeiss for Flak 8,8 cm U-Bootskanone L/30, about 1915
U-Boot Zielfernrohr or pointing telescope, produced by Carl Zeiss in about 1915, and in use on the Cannon called Ubts.u. TBTS. Flak L / 30 8.8 cm Krupp, 264 cm long, installed on board of the U-Boot class U-19 of the Kaiserliche Marine (German Imperial Marina), used during World War I. The U-Boot Class U-19 is to be remembered for the U-20, famous for sinking the largest number of ships, among which the English Transatlantic "RMS Lusitania" in 1915.
The pointing optic, whose structure is made of marine bronze, is equipped with a tube at its end with a glass, secured by a hand-held snap-on lid, which allows it to reduce the resistance produced by the water on its own structure during dive navigation. A perforated and rotating ring on the tube itself allows the water to flow out once on the surface making it ready for the use of the pointing. The objective lens, of considerable thickness, is also protected by a "watertight" glass flange which protects it from pressure and further protects it from any water infiltration. Inside the ocular compartment there are 4 colored filters (Clear, Light Gray, Green, Orange) with swivel insertion via knob.
What makes exceptionally rare this U-boot Zielfernrohr is the presence of a small lever on the eyepiece, which reports "Dunkel" and "Hell" (Dark and Light) to indicate the presence of a small auto lightening device, Made with "Radio or Radium" particles, suitable for lighting the reticle in case of poor visibility.
Analyzing the exemplar described and considering that no optics at the time was equipped with internal electric illuminators (the first external electric illuminators were invented to 1910/12 and applied only to microscopes) we can state that this pointing pointfinder for U-Boat was one of the first (maybe the first) optical instrument to adopt and benefit from a state-of-the-art technology: the Radio or Radium which was discovered by the Curie spouses in 1898. This lighting system will find it again after some Decade applied to the famous 7x50 U.D.F. Binoculars or UZO in use at Kriegsmarine (these were installed as auto-illuminating "Trizio" particles extrapolated from Radio since 1934).
Carl Zeiss takes its name from its founder, Carl Zeiss, who on November 17, 1846 chose the small city of Jena, in Thuringia, as the location for his precision optical equipment factory. Thanks to the strict quality control that Carl Zeiss imposed on its products, going so far as to personally destroy the microscopes that did not pass the tests, the newborn Zeiss became the official supplier of the University of Jena and received the gold medal of the industrial exhibition in 1861 of Thuringia as the best research instrument produced in Germany, awarded to the Stand I microscope of 1857.
In 1866 the thousandth microscope was produced and the name Zeiss became known throughout European scientific circles. Thanks to studies on the Porro prism, in 1893 Abbe patented double prism binoculars, which accentuated the perception of depth. The mass production of Zeiss binoculars began in 1894, already at the beginning of the twentieth century more than 30,000 were made, by the beginning of the First World War the figure had risen to 500,000 and, by the end of the Second World War, 2,260,000 were produced binoculars for the civil and military market. Models were made starting from 4x11 mm to 12x40 mm, up to real giants such as the 80 mm and 100 mm. Thanks to studies conducted on the perception of light in low light situations, it was shown that the average dilation of the pupil in an adult is about 7 mm. For this reason, the 7x50 mm model was introduced in 1910 and remained on the market until 1917 with few changes to the materials used.
In 1926, following the post-war crisis of the First World War with the Treaty of Versailles which bankrupted many important German companies, Zeiss bought the "C.P. GOERZ" and founded the Zeiss Ikon in 1926. In 1937 Zeiss had commercial contacts and factories in more than 29 countries around the world. From '33 Zeiss acquired interest from the Nazi regime, which balanced production towards military instruments. It successfully produced binoculars with wide-angle optics for military use, pressure resistant optical systems for U-boats, periscope binoculars for targeting tanks. Furthermore, Zeiss cameras were mounted on the V2s for remote sensing operations of the English coasts.
On November 1, 1935, Zeiss, in the person of Alexander Smakula, patented a process for the treatment of optical glasses with extraordinary results in terms of light transmission. Remained a military secret until 1939, it was adopted on binoculars to reduce ghost images and internal reflections. During the Second World War, there were numerous bombings against the Zeiss factories. Jena was bombed several times by the Allies starting in 1944. Stuttgart was razed to the ground, although the Contessa-Nettel factory suffered little damage. The bombing of Dresden, in addition to devastating the city, also caused considerable damage to the Zeiss Ikon headquarters.
On April 13, 1945, American military forces entered Jena, surprising themselves that the bombing had not caused any significant damage. The main planetarium was in ruins, while the factories remained operational.