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

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)

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