Figure 3. Refracted horizontal angle dhr and horizontal shift. Above: positive and below: negative refracted angle. The photos were modified by (https://simple.wikipedia.org/wiki/Refraction)

From

Improved Model of Refracted Horizontal Angle: Dependency on Zenith Angle

Mansoor Sabzali, Lloyd Pilgrim

American Journal of Civil Engineering and Architecture. 2023, 11(2), 38-44 doi:10.12691/ajcea-11-2-2