The periscope on the left uses mirrors whereas the right uses prisms. The two periscopes differ in the way they erect the image. The left one uses an erecting prism whereas the right uses an erecting lens and a second image plane.Ī periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position. In its simplest form, it consists of an outer case with mirrors at each end set parallel to each other at a 45-degree angle. Its a great lens The glass is clean and the shutter works well on all positions. This form of periscope, with the addition of two simple lenses, served for observation purposes in the trenches during World War I. Gundlach Radar- Extreme Wide Angle Lens in shutter for 8x10(20x25cm) Large Format Camera. Military personnel also use periscopes in some gun turrets and in armoured vehicles. More complex periscopes, using prisms and/or advanced fiber optics instead of mirrors, and providing magnification, operate on submarines and in various fields of science. The overall design of the classical submarine periscope is very simple: two telescopes pointed into each other. Photograph by Ernest Brooks.Ī team of German artillery observers using periscope binoculars, 1943 If the two telescopes have different individual magnification, the difference between them causes an overall magnification or reduction.Īustralian Light Horse troops using a periscope rifle, Gallipoli, 1915. Gundlach Radar Anastigmat 12 Inch 8X10 Front Element Cell Group - VERY NICE - 75.00 Buy It Now +10.00 shipping Sponsored New Listing 12-WB standard blade, 12 pack, benjo j Gundlach co 4 PACKs OF 12 48 blades Brand New 1.99 0 bids 9d 13h left (01/05, 07:40 PM) +12. Johannes Gutenberg, known for his contribution to printing technology, marketed a kind of periscope in the 1430s to enable pilgrims to see over the heads of the crowd at the vigintennial religious festival at Aachen. Johannes Hevelius described an early periscope with lenses in 1647 in his work Selenographia, sive Lunae descriptio. Hevelius saw military applications for his invention. In 1854 Hippolyte Marié-Davy invented the first naval periscope, consisting of a vertical tube with two small mirrors fixed at each end at 45°. Simon Lake used periscopes in his submarines in 1902. Sir Howard Grubb perfected the device in World War I. ![]() Morgan Robertson (1861–1915) claimed to have tried to patent the periscope: he described a submarine using a periscope in his fictional works. Periscopes, in some cases fixed to rifles, served in World War I (1914-1918) to enable soldiers to see over the tops of trenches, thus avoiding exposure to enemy fire (especially from snipers). ĭuring World War II (1939-1945), artillery observers and officers used specifically-manufactured periscope binoculars with different mountings. Some of them also allowed estimating the distance to a target, as they were designed as stereoscopic rangefinders. Tanks use periscopes extensively: they enable drivers or tank commanders to inspect their situation without leaving the safety of the tank. #Gundlach radar extreme wide angle lens drivers# An important development, the Gundlach rotary periscope, incorporated a rotating top this allowed a tank commander to obtain a 360-degree field of view without moving his seat. This design, patented by Rudolf Gundlach in 1936, first saw use in the Polish 7-TP light tank (produced from 1935 to 1939). As a part of Polish–British pre- World War II military cooperation, the patent was sold to Vickers-Armstrong for use in British tanks, including the Crusader, Churchill, Valentine, and Cromwell models. The technology was also transferred to the American Army for use in its tanks, including the Sherman. ![]() #Gundlach radar extreme wide angle lens drivers#.And, we've been underweight until very recently emerging market debt as well," added Gundlach. We've been in zero emerging market equities this whole time. "I kind of think the next move, the big move is to enter emerging markets. ![]() Gundlach is increasingly more optimistic on emerging markets, minus China (which he doesn't think is an emerging market anymore). The Wall Street Journal points out the total value of China's onshore stocks rose 20% in 2021, underperforming the S&P 500's advance. The investing headwinds in the country show up in how the country's key indexes performed in 2021.įor instance, the Golden Dragon Index - which tracks the performance of mid- and large-cap Chinese stocks - plunged about 49% in 2021. Meanwhile, the long reach of China's government also hammered after-school tutoring companies such as TAL Education Group - shares of the name plunged about 95% in 2021.Īll of this is in addition to China's ongoing fight against the rise of cryptocurrencies. DoubleLine founder Jeffrey Gundlach (right) tells Yahoo Finance China is uninvestable.
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