The Astronomical Observatories of Jai Singh c11.s2.t1.39

c11.s2.t1.39

“But what attracts most attention is a gnomon (axis mundi), remarkable for its height of 70 Paris feet,² and for its thickness—constructed in brick and lime, situated in the plane of the meridian, with an angle equal to the height of the pole. On the summit of this gnomon is a belvedere, which overlooks all the town and is so high that it makes one giddy. The shadow of this gigantic gnomon falls on a prodigiously large astronomical semi-circle, of which the horns are turned towards the sky. It is artistically constructed in whitest lime or gypsum, and is graduated in degrees and minutes. In the morning the shadow falls on the western quadrant, and in the evening on that towards the east, and, as the gnomon lies between both the quadrants, the sun's altitude can be found at any moment. A double dial, constructed also in lime, is seen near these quadrants. It is enclosed in a kind of chamber, on either side of which it is raised. When the sun passes the meridian a ray of this star enters through each of two holes pierced in a sheet of copper, and when these rays fall exactly on the middle of the two quadrants, low in summer and higher in winter, the sun is in the meridian sign, and its meridian height is indicated.