Looking for the Wndsn store? This way, please.

Wndsn Quadrant Telemeters

Wndsn Graphical Telemetry Computers: Low tech, high utility distance and altitude nomographs from the Wndsn applied science lab

Reference Materials

Tables, conversions, and the manual.

Multipliers for a Given Angle

For D = S * 1/tan(α) in 0.1° increments between 0.1° and 12°.

Use: For a measured angle α, multiply the known size of the object by the value in 1/tan(α) to determine the distance.

α 1/tan(α) ×180/π/α
0.1 573.0
0.2 286.5
0.3 191.0
0.4 143.2
0.5 114.6
0.6 95.5
0.7 81.8
0.8 71.6
0.9 63.7
1 57.3 ×180/π/1
1.1 52.1
1.2 47.7
1.3 44.1
1.4 40.9
1.5 38.2
1.6 35.8
1.7 33.7
1.8 31.8
1.9 30.1
2 28.6 ×180/π/2
2.1 27.3
2.2 26.0
2.3 24.9
2.4 23.9
2.5 22.9
2.6 22.0
2.7 21.2
2.8 20.4
2.9 19.7
3 19.1 ×180/π/3
3.1 18.5
3.2 17.9
3.3 17.3
3.4 16.8
3.5 16.3
3.6 15.9
3.7 15.5
3.8 15.1
3.9 14.7
4 14.3 ×180/π/4
4.1 14.0
4.2 13.6
4.3 13.3
4.4 13.0
4.5 12.7
4.6 12.4
4.7 12.2
4.8 11.9
4.9 11.7
5 11.4 ×180/π/5
5.1 11.2
5.2 11.0
5.3 10.8
5.4 10.6
5.5 10.4
5.6 10.2
5.7 10.0
5.8 9.8
5.9 9.7
6 9.5 ×180/π/6
6.1 9.4
6.2 9.2
6.3 9.1
6.4 8.9
6.5 8.8
6.6 8.6
6.7 8.5
6.8 8.4
6.9 8.3
7 8.1 ×180/π/7
7.1 8.0
7.2 7.9
7.3 7.8
7.4 7.7
7.5 7.6
7.6 7.5
7.7 7.4
7.8 7.3
7.9 7.2
8 7.1 ×180/π/8
8.1 7.0
8.2 6.9
8.3 6.9
8.4 6.8
8.5 6.7
8.6 6.6
8.7 6.5
8.8 6.5
8.9 6.4
9 6.3 ×180/π/9
9.1 6.2
9.2 6.2
9.3 6.1
9.4 6.0
9.5 6.0
9.6 5.9
9.7 5.9
9.8 5.8
9.9 5.7
10 5.7 ×180/π/10
10.1 5.6
10.2 5.6
10.3 5.5
10.4 5.4
10.5 5.4
10.6 5.3
10.7 5.3
10.8 5.2
10.9 5.2
11 5.1 ×180/π/11
11.1 5.1
11.2 5.1
11.3 5.0
11.4 5.0
11.5 4.9
11.6 4.9
11.7 4.8
11.8 4.8
11.9 4.7
12 4.7 ×180/π/12

Shop Wndsn Telemeters