Solar azimuth angle be interpreted as the angle between zero and 180 degrees when the hour angle, "h", is negative (morning) and the angle between 180 and 360 degrees when the hour angle, "h", is positive (afternoon). (These two formulas are equivalent if you assume the "solar elevation angle" approximation formula). The formulas use the following terminology: Solar azimuth angle The solar azimuth angle is the azimuth angle of the Sun's position. This horizontal coordinate defines the Sun's relative direction along the local horizon, whereas the solar zenith angle (or its complementary angle solar elevation) defines the Sun's apparent altitude. There are several
Perceived visual angle specifies the amount by which one should rotate one's eye to quickly look from one seen point to another eye tracking, saccade, observers in other experiments shifted their gaze from one object endpoint to the other, and the angle the eye rotated through was measured as "θ′" for that object (Yarbus (1967). It is important to understand how "θ′" differs from "S′". Consider an example illustrated by the sketch at the right. Suppose one is looking through a window at a house 240 feet away, so it subtends a visual angle of about 7 degrees. The window opening is 10