Determination of the Declination of the Sun on a Given Day

In this article we discuss a novel and low cost experiment to determine the angle of declination of the sun on a chosen day. The declination of the sun varies from + 23.5 degrees to - 23.5 degrees in the course of one year. If the zenith angle of the sun is measured as a function of its hour angle on a particular day, it is possible to calculate the angle of declination by using of spherical trigonometric relationship between them. The zenith angle is determined by using the shadow length of a vertically placed rod. The hour angle is determined from the position of shadow as a function of time. The value of solar declination may be compared with that available in almanacs.