Posted by Jarrad Michael on .
The diameter of the sun makes an angle of .53 degrees from earth. How many minutes does it take for the sun to move one solar diameter in an overhead sky? ( Remember that it takes 24 hours or 1440 minutes for the sun to move through 360 degrees).
How does your answer compare with the time it takes for the sun to disappear once its lower edge meets the horizon at sunset?
Does defreaction affect the answer?
.53/360 = x/1440
The sun's angular speedin the sky is 360 degrees/1440 min = 0.250 degrees/min
The time to move one solar diameter is
T = (0.53 deg)/(0.25 deg/min) = 2.1 min
Make your own observation of the actual sunset time. Refraction is one reason for a discrepancy. So is the angle that the sun's path makes with the horizon. It sets obliquely, not perpendicular to the horizon at temperate and polar latitudes.