सिद्धान्तशिरोमणि: गणिताध्याय (भास्कराचार्य - ग्रहगणित, मध्यमाधिकार व स्पष्टाधिकार सटीक)

463
Fig. 110
Dṛk-karma. (This correction is given by the arc p'q).
The difference of the rising times of the planet p and q
expressed in asus is what is sought here. The planet p
rose at a and has covered the arc ap of the diurnal circle
after rising. So, we have to compute ap and therefrom
the corresponding arc of the Equator namely AC. If the
planet has no latitude ie. is situated on the ecliptic at p',
the arc p'q or Āyana Dṛk-karma vanishes, for, the Āyana
Dṛk-karma is no other than the projection of the latitude
of the planet on the ecliptic taking P or celestial pole as
the vertex of projection. Also if there were no Akṣa ie.
if the place be equatorial, p and q rise simultaneously ie.
the planet will rise along with the point called Kṛta-
Āyana-Dṛk-Karmaka-Sthāna q, mentioned above. In fact
the Dṛk-karma corrections Āyana and Ākṣa are contem-
plated to obtain the difference in the rising times of p and
p' ie. the planet and its position on the ecliptic. This
time is resolved into two parts (i) the difference of the
rising times of p' and q and (ii) that of the rising times
of q and p. The former is given by the equatorial arc
BC which goes by the name Āyana-Dṛk-karma and the
latter by the arc AC which goes by the name Ākṣa-Dṛk-
karma. The algebraic sum of these two corrections gives
the difference of the rising time of p and p' ie. the time
given by the arc AB. Here AB=AC-BC, In verses