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Wndsn Expedition Team

Ex Mensura, Scientia

Wndsn Range Calculator

High-precision range calculator. Companion to Wndsn Telemeters: Low tech, high utility graphical distance & altitude computers from the Wndsn applied science lab.

By way of using a Wndsn Quadrant or Telemeter measuring degrees or a hairline graticule measuring mil or moa or any other instrument or technique that returns the angular size of a known object, we can determine the distance to that object.

Calculate range.

The angular relationship between height and distance.

Input

Determine distance d (use any unit (cm, mm, inches, etc.) for s, at angular size α)
Reset

Results [XML]

  • Angular size: 5.7 degrees or 99.4821 MIL (MRAD) or 101.3333 MIL (NATO-MIL) or 342 MOA [increase precision]
  • Distance multiplier: d = s · 1/tan(5.7°) = s · 10.0187

The display precision set is .4. To change that, edit the variable &digits=x in the URL where 0 <= x <= 9.

Explanation

[Load sample values (JSON) (XML) (CSV).]

Compare MIL vs. MRAD vs. NATO-MIL.

1/tan(α)
  • 1/tan(5.7°) returns a distance multiplier for d = s · 10.0187.
  • Using the Quadrant Telemeter's shadow square makes it possible to convert a given or measured angular size to the multiplier 1/tan(α), according to the formula: distance = known size · [shadow square length]/reading, where [shadow square length]/reading = 1/tan(α).

Reference

1        rad =  57.3     deg
6.2832   rad = 360       deg = 6,283.2   mil = 6,400     natomil = 21,600     minutes (moa)
0.017453 rad =   1       deg =    17.453 mil =    17.778 natomil =     60     minutes (moa)
                 0.0573  deg =     1     mil =     1.019 natomil =      3.438 minutes (moa)
                 0.05625 deg =     0.982 mil =     1     natomil =      3.375 minutes (moa)

Radian, degrees, mrad, NATO-MIL, and MOA.

See also