The concept of astrology is based on the movement of the earth and surrounding planets. The center of the universe being the SUN. The position of SUN signifies the human soul, the MOON signifies the human mind and the position of EARTH which means the ascendant or "LAGNA" this signifies the HUMAN BODY. It is the combination of the three i.e. the MIND, BODY and SOUL that makes a perfect human being. The whole UNIVERSE is divided into 12 parts each one being 30 degrees, hence the total circumference of the earth is 360 degrees (12 signs into 30 degrees each). The rising sign at a certain longitude determines the descendent or "LAGNA". There are a total of 27 Constellations and each constellation has 4 PADAS" and thus in total 27 X 4 = 108 "PADAS". It is the position of the MOON viz.