Distance in Miles:

Viewer height in Feet:

Distance = ?, View Height = ? Actual Radius = ?

With "Standard" refraction adjustment of 7/6 radius (?)

Refracted Horizon = ?

Refracted Drop= ?

Refracted Hidden= ?

Refracted Horizon Dip =

Note: Not accurate for observations over water very close to the horizon

Geometric results (no refraction)

Geometric Horizon = ?

Geometric Drop =

Geometric Hidden=

Geometric Horizon Dip =

Pure Angular Size results (Explanation Here)

Angle between eye level and the horizon =

Angle between eye level and the bottom of the target=

Angular size of hidden amount =

"Standard Refraction" is an approximation of the refraction expected under average or Standard Atmospheric conditions.

Actual atmospheric conditions can vary greatly, and the resultant refraction can be complex, especially close to the horizon.

See here for the source of this approximation. See here for historical usage of this approximation

For a more detailed simulation of the effects of refraction, see the Metabunk Refraction Simulator

The image below is interactive, you can drag the three red dots , zoom and move. It illustrates the relationship between the various numbers, not the actual values.