For our purposes, it is convenient to assume that the earth is stationary and the sun is in motion around the earth. Figure V-1 lists the angle (declination) of the sun above (+) or below (-) the equator, on the twentieth of each month, as seen from the earth. From the Northern Hemisphere, you can … Read more
A sundial is a device that uses the position of the sun to tell time. Sundials work by casting a shadow on a marked surface, with the length and direction of the shadow indicating the time of day. The earth’s declination, or the angle at which the earth’s axis is tilted relative to its orbit … Read more
A good sundial has the shadowing edge parallel to the earth’s axis of rotation. The angle of rotation then is measured as the shadow move in a plane perpendicular to the earth’s axis. This can be constructed by sticking a broomstick out from the roof on ones house at an angle with respect to the … Read more