World War II Naval Optics: Kollmorgen 20x120
A brief history of Kollmorgen
Frederick Kollmorgen was a German skilled in optics who, after some time honing his craft in Vienna and London, came to New York in the early 1900’s. When the US Navy placed a bid for periscopes, Kollmorgen decided to start his own company. Building on his own knowledge and experience, he developed the best periscope optical sets in the United States with French optical glass.
After the First World War, Kollmorgen switched over to the entertainment industry building quality projection lenses for movie theaters. When the Great Depression hit, Kollmorgen turned to producing ashtrays by repurposing rejected lenses to keep afloat. It wasn’t until the US engaged in World War II that the economy and industry kicked back into gear. The Kollmorgen Optical Company profited from this new development through government-funded development work. Optical devices were in high demand again and the company produced driftmeters, bombsights submarine periscopes and sophisticated navigation instruments. During that time of profit and success, they were also the first to start using anti-reflective coating on lenses.
It was around that time submarine periscopes became a very important and profitable part of Kollmorgen’s business. That is because in 1940, submarines realized that aircrafts posed a major threat to them, causing the Bureau of Ships to develop a periscope, the “needle nose” Type 1 attack design. Kollmorgen took that design and improved it: the Type 2 featured a tube tapered at its head, which reduced the surface wake. The field of view was extended to 90.5 degrees of elevation so the periscope could cover the entire sky. The type 2 periscope remained a valuable asset into the 1990s, small design tweaks notwithstanding.
The 20x120 naval optics
The Kollmorgen 20x120 is one of the largest pairs of ships binoculars ever used by the U.S. Navy. They were copied from captured Japanese Navy ships. Where the Japanese Navy had up to a dozen of these 20x120 Big Eye’s on the deck, the U.S. Navy would only mount one pair of Kollmorgen 20x120 binoculars on the railing of the Signal Deck.
The 20x120 binoculars were manufactured in the 1960’s by the Kollmorgen Optical Company in Northampton, Massachusetts. The coated 120mm objective lenses have a huge field of view of 3.5 degrees, with an apparent field of view up of up to 70 degrees. The 1-¼ inch eyepieces focus internally and have individual external focusing knobs geared to the internal lenses. These Kollmorgen binoculars also boast built-in, adjustable rubber sunshades that would protect the viewer when the ship was underway.
Underneath the eyepiece housing, there are two levers: the right lever controls the interpupillary distance and the left the built-in polarizing filters. The eye relief is 20mm, and the minimum focusing distance is 400 feet. Most of these 20x120 naval optics manufactured by the Kollmorgen Optical Company featured an aluminum mounting adapter on the bottom with a threaded 3/8” hole to easily mount on any heavy-duty tripod. It also featured refillable desiccant chambers and was completely sealed against the elements, as well as being waterproof.
The 20x120 naval optics were usually finished in the classic Navy grey and measure 22” long, 15” wide and weighed 33 lbs.