Ayanamsa is the longitudinal difference between the sidereal zodiacs or Nirayana and the Tropical zodiacs or Sayana. So far as the type of difference is concerned, this is the angular difference between the tropical and the sidereal longitudes. There are three methods of ayanamsa calculation, namely, Lahiri Ayanamsa calculation, KP ayanamsa calculation and Raman ayanamsa calculation. You might wonder why it is necessary to know the difference between the sidereal and tropical longitudes. Such differences bring out the exact information regarding the position of your birthplace and also the astrological planetary positions. Again, such accurate details about planetary positions are necessary for the generation of a perfect horoscope or natal chart. The significance of ayanamsa is that if the exact birth place, the time of birth is provided.It also tells you everything about your nature, personality traits and also the various possibilities in your life.