 Commentary by Rudra titled - "Vivarna" though based on Dasadhyayi of Talakkulathur Govinda Bhattathiri is considered to be the superior of these two.Jyotisa, allied to metaphysics, has a philosophical background and aim.A disciplined body, mind and spirit makes one adept in Jyotisa which feature emerges prominently in Brihat Jataka as a basic work on this science and which feature is also brought out with remarkable clearness and force in various commentaries on this text including that of A.N.