Geocentric ecliptic longitudes of the planets and the sun from Gili and Biruni compared with modern calculations

A comparison is made of the geocentric ecliptic longitudes of Mercury, Venus, the sun, Mars, Jupiter, and Saturn between 632 and 1452 AD as observed by the medieval astronomers Gili and Biruni, and modern longitudes calculated from the osculating and mean orbital elements. It is found that the true longitudes of Mars, Jupiter, and Saturn obtained by the mean orbital elements method are not significantly different from the estimates of Gili and Biruni. A comparison of the geocentric coordinates of the planets calculated from the osculating elements and those determined on the basis of rectangular elements over a period of 3000 years indicated no difference in the ecliptic longitudes and latitudes of the planets.