SIDA Earth Parameters Measurement Slide Rule

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Country of manufacture: China,            Date of manufacture: ____
Overall length: 28.1 cm,          Width: 3.9 cm,           Weight: 92.9 gms
Materials: Simplex construction, celluloid laminate over wood
Cursor: 4.1 X 3.7 X 0.6 cms; plated metal frame holding glass lens; lines = single hairline
Scales: 12
Front: Y_KM (90-350)/1-Cos (1°- 2°30') // 1-Cos (2°30' - 25°), N² [ n², Sec², T (1°- 5°45'), T (5°45'- 45°) ] N, L || l_CM
Slide Back: S, n
Gauge Marks: [      ]
Back: physical constants, correction factors, formulae
Condition: C5 (Normal signs of use)
Came with: Orig. gray cardboard case

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