IMG_3594

The Pam Yantra can measure the altitude and azimuth of a celestial object.
The angular height of an object from the horizon is the altitude. The azimuth is the relative angular position of the object measured eastwards, starting from the direction North. The complementary units are so designed that the shadow of the gnomon falls on a Sector of one of the instruments if it falls in the gap for the other instrument.

When the shadow falls at the top of the wall of the instrument, the altitude of the Sun is zero. When the shadow is at the junction between the wall and the floor, the altitude of the Sun is 45 degrees. Altitudes between 45 and 90 degrees can be read in a radial direction on the floor of the instrument.