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20 X 120 Kollmorgen Mark I 45-degree Binoculars

Kollmorgen 20 X 120 is known as one of the most massive “Navy Big Eyes” ship binoculars used by the U.S. Navy. U.S. Navy ships would mount a 20 X 120 Big Eye binocular on the deck just off the bridge. The 45-degree lens angle provided ease of use aboard ship where lookouts could spend hours scanning the horizon.

Long-range military observation relied on Big Eye binoculars since the late 19th century. They were preferred for their large magnification, which gave a significant advantage out at sea.

Reportedly, during WWII the design was reverse engineered from Big Eyes captured from Japanese Navy ships. While the U.S. Navy usually only had the one mounted near the bridge, Japanese Navy ships would have up to a dozen installed in various locations.


Kollmorgen did not start their business building binoculars. From WWI to 1958, Kollmorgen was the preeminent designer and supplier of submarine periscopes to the U.S. Navy. Dr. Friedrich Kollmorgen set the standard with his two-telescope design that carries on today.

Dr. Kollmorgen and his wife arrived in the U.S. in 1905 as German immigrants. With the high demand for periscopes for the looming WWI, Kollmorgen Optical Corporation incorporated in 1916 to meet the challenge.

Soon after the war, the demand for periscopes dropped, but movies became big business, and quality projection lenses were needed. Dr. Kollmorgen always saw opportunities as they presented themselves.

The depression hit in the early 1930s, leaving most of America out of work until the emergence of WWII. Kollmorgen ramped up again with government contracts to build drift meters, bombsights, navigational instruments – and periscopes. Kollmorgen is the first to use anti-reflecting coating on lenses.

The company grew from 60 to over 600 employees in just five years during WWII. They also designed and built remote viewing devices for the “Manhattan Project.”

Kollmorgen 20 X 120 binoculars were manufactured in the 1960s during the Cold War, after the company relocated to Northampton, Massachusetts.


These 20 X 120 binoculars are great for astronomy as they perform beautifully in low-light conditions. However, they are quite large and can be quite heavy, so they must be mounted either permanently or on a heavy-duty stand.

If you enjoy the industrial look, you can keep them in their original glory painted with Navy grey paint, or have them polished down to a shiny brilliance and they will become a focal point in your home, office, or on the deck of your yacht. As a functional piece of art, you will enjoy star gazing in style.


· 120mm coated objective lens

· 45-degree offset eyepieces using rhomboid prisms

· Field of View – 3.5 degrees

· Apparent Field of View up to 70 degrees

· 1 ¼ inch internal eyepiece focus

· Individual external focusing knobs

· Built in adjustable rubber sunshades

· Interpupillary distance controls

· Built-in polarizing filters

· 20mm Eye relief

· Refillable desiccant chambers

· Completely sealed and waterproof

· 22 inches long, 15 inches wide

· Weight: 33 pounds

Here we have a pair of the most unique pair of 20x120 Kollmorgen Mark 1 Binoculars, that have been fully restored by our Us Navy Optician.


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