Why do the times of sunrise/sunset appear to not change with height above the earth?
MICA assumes a level horizon in its calculation of rise/set. This means that the dip of the horizon is not taken into consideration when calculating the times. However, the refraction of the light does change, because the light at altitude is not passing through as much atmosphere as it does at sea level. In most circumstances these changes are small, usually less than a minute in rise/set time. Since the rise/set times are printed only to the nearest minute, you won’t usually see any differences. However, at high latitudes, the times can change by several minutes (see the example for Barrow, Alaska below).
