Description
U.S. Antiaircraft Battery Commander’s Observation Instrument M1 Mount, No. 83, Frankford Arsenal, 1936
Item Overview
This U.S. Army Antiaircraft Battery Commander’s Observation Instrument M1 is a tripod-mounted fire-control observation instrument from the pre-World War II period. It allowed an observer and battery commander to track a moving aircraft, observe trial-shot bursts, measure their position from the target, and report corrections in mils. The instrument could also measure the azimuth and elevation needed to orient an antiaircraft battery in place of a surveyor’s transit. This example is serial No. 83 and is marked for Frankford Arsenal, 1936, and the Experimental Design Board. The sale includes the observation-instrument mount and its telescope clamps, but not the original telescopes or tripod.
Identification and Features
The identification plate reads “INSTRUMENT, OBSERVATION, A.A., B.C., M1,” with serial No. 83, “F.A., 1936,” and “E.D.B.” In this nomenclature, A.A. means Antiaircraft, B.C. means Battery Commander’s, F.A. identifies Frankford Arsenal, and E.D.B. identifies the Experimental Design Board. TM 9-1665 states that instruments numbered 1 through 1123 used the Telescope M3 for the battery commander, While later serial numbers were paired with the Telescope Elbow M35. A separate 8-power Elbow Telescope M2 was used by the observer. The mount includes azimuth and elevation scales, micrometers, bubble levels, traverse and elevation controls, illumination provisions, and separate mounting clamps for both telescopes.
- Official designation: Antiaircraft Battery Commander’s Observation Instrument M1
- Serial number: No. 83
- Manufacturer marking: F.A., Frankford Arsenal
- Production date: 1936
- Designer marking: E.D.B., Experimental Design Board
- Azimuth range: 0–6,400 mils
- Azimuth measurement: Within 0.1 mil
- Elevation range: 0–1,500 mils
- Elevation measurement: Within 1 mil
- Battery commander’s telescope application: Telescope M3, 10× or 20×
- Observer’s telescope application: Elbow Telescope M2, 8×
- Governing manual: TM 9-1665, dated March 2, 1943
Historical Background
The U.S. Army described the M1 as its standard antiaircraft observation instrument during the World War II period. This 1936 example predates both the March 1939 regulation and the March 1943 technical manual that later documented the system. In normal operation, the observer looked through the Elbow Telescope M2 and used the traverse and elevation controls to keep a moving aircraft near the center of the reticle. The battery commander observed through the Telescope M3 and measured the horizontal and vertical distance between the target and the shell bursts. These deviations were read in mils and reported for fire correction. The instrument could also observe rapidly moving ground targets, check trial shots from a distant observation station, and provide azimuth and elevation information for orienting the battery. It operated as a separate observation station rather than as a sight mounted directly on an antiaircraft gun. TM 9-1665 superseded Technical Regulation TR 1320-DO of March 14, 1939, showing the instrument’s continued place in wartime Army maintenance and fire-control documentation.
Condition
This is an original 1936 military-surplus observation-instrument mount. It retains its identification markings, scale assemblies, levels, traverse and elevation controls, and the empty mounting clamps for the Telescope M3 and Elbow Telescope M2. The Telescope M3, Elbow Telescope M2, Type A tripod, battery box, electrical leads, and packing chests are not included. The finish may show age-related patina, scratches, worn paint, oxidation, and other storage or handling wear.
Ideal For
This well-marked 1936 example offers collectors a substantial piece of prewar American antiaircraft fire-control equipment. The low serial number, Frankford Arsenal marking, Experimental Design Board marking, and documented Telescope M3 application give it strong identification value. It can be displayed as is, mounted on a suitable tripod, or used as the foundation for a historically accurate restoration with the correct M3 and M2 telescopes.
- Pre-World War II and World War II collections
- U.S. antiaircraft artillery displays
- Frankford Arsenal collections
- Military optical and fire-control equipment collections
- Telescope M3 and Elbow Telescope M2 displays
- TM 9-1665 restoration projects
- Military surveying and battery-orientation exhibits
Approx length 12", Approx width 10", Approx height 14", Approx weight 27lbs.
Pictures are stock images of our inventory. Unless otherwise noted, you will not be receiving the exact item shown in the pictures. The pictures are representative of the item’s general condition. The item you receive might be slightly better, or worse, condition than was shown in the pictures.
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