Astrological calculations are called jyoti-śāstra. Because the jyoti, or effulgence, in the material world comes from the different stars and planets, the science is called jyoti-śāstra, the science of the luminaries. By the calculations of jyoti, our future is indicated. In other words, all the luminaries — the stars, sun and moon — witness the activities of the conditioned soul. Thus he is awarded a particular type of body.