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

438
Verses 18, 19. To obtain the true values of the Bhuja
and the Iṣṭakāla.
The remaining work proceeds on the lines indicated
in the chapter on ‘lunar eclipses’ (ie. the computation of
the Bimbavalana, Bhuja, Koti and the like is to be done
as indicated there). The Bhuja will be rectified by multi-
plying it by the Sthiti-khanda obtained by adopting the
latitude of the Moon effected by parallax in latitude and
divided by the Sthiti-khanda rectified for parallax in
longitude. Similarly given the grāsa ie. the magnitude
of the eclipse, the result found before by verse 15 in the
chapter of lunar eclipses, is to be multiplied by the Sthiti-
khanda rectified for parallax in longitude and divided by
that obtained adopting the latitude of the Moon effected
by parallax in latitude, and the result so obtained being
subtracted from the Sthiti-khanda, we get the Iṣṭa-kāla.
Comm.