The Distance of the Sun from the Earth

Abstract

The distance of the sun is calculated from the parallax of height. It is extremely difficult to compute this parallax since one must reckon in advance the true altitude of the sun from its motion so as to distinguish the difference between its true and apparent height. The true motion of the sun and its position in the heavens, however, cannot be found with such precision (because the sun’s great distance allows no proportion to be made with respect to the earth’s radius) and inaccurate calculations in minutes and seconds are bound to result. Astronomers, therefore, found other means and used the moon for this at first.