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

With the refraction approximation* giving an effective radius of ?

Refracted Horizon = ?

Refracted Drop= ?

Refracted Hidden= ?

Refracted Horizon Dip =

Note: Not accurate for observations over water very close to the horizon (unless the temperature and vertical temperature gradient are accurate)

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 =

* The default values for the refraction approximation (see the Advanced checkbox) produce an effective radius of (7/6)*R. The default pressure is 1 atmosphere and the default vertical temperature gradient is the dry adiabatic lapse rate (negated).

"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.