Observation, 85 mm
These binoculars are used for general observation upon a tripod for which an adapter is provided on the instrument. An elevation scale is etched on the reticle and the 90° prisms are cemented. Two steel bands connect the eyepieces mechanically. Drying bents are contained in each telescope.
Aircraft Spotting, 100 mm
The telescope bodies of this instrument are of cast aluminum; the fittings are of brass. The erecting system consists of a roof angle prism held in position by four screws. The objective is housed in an eccentric adapter. The eyepieces are offset from the main tube. Interocular settings are obtained by rotating the eyepiece housings. There are two drying plugs in the body of each telescope.
Aircraft Spotting, 120 mm
It is believed that this improved model is replacing the 100 mm binoculars described above. The eyepiece assemblies include a rhomboid prism. Inter-ocular distances are varied by rotating the left eyepiece assembly. The erecting system consists of one porro prism and two 90° prisms cemented to the porro system.
A feature of this instrument is the dehydrating unit consisting of a silk bag of silica gel placed in a perforated metal holder fitted between the two telescope assemblies. Drying vents are also provided.
SPECIFICATIONS
| 85 mm | 100 mm | 120 mm | ||||
| Power | 15X | 15X | 20X | |||
| Field of view | 4° | 4° | 3° | |||
| Interobjective distance (approx.) | 4 7/16 ins. | 5 9/16 ins. | 7 ins. | |||
| Diopter movement | +2 to -4 | +2 to -3 | +2 to -4 | |||
| Interpupillary movement | 60 to 72 mm | 60 to 72 mm | 58 to 72 mm | |||
| Length | 18 ins. | 21 1/2 ins. | 24 ins. | |||
| Width | 18 1/2 ins. | 16 ins. | 18 ins. | |||
| Weight | 21 1/2 lbs. | 32 lbs., 12 ozs. | 50 lbs., 8 ozs. | |||
| Manufacturer | Jap. Op. Co. | Jap. Op. Co. | Toyko Optical Mach. Stock Joint Co. | |||
| Serial number | 915 | 2254 | 63 |
Japanese: p. 183 (March 1, 1945)