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

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This happens when the star has a long northern latitude
and therefore the Ākṣa-Dṛk-Karma correction will be
sufficiently large and the star has a small north polar
distance. This may be substantiated as follows.
Fig. 122
We have the formula cos h = — tan ϕ tan δ which
gives the rising hour-angle of the star. When δ is nearly
equal to 90—ϕ, then cos h will be nearly equal to ‘—1’
which means that the rising hour angle is nearly equal to
180°, ie. the duration of the star’s stay below the horizon
will be very small. This means A' approaches A very
nearly (fig. 121), for example when it is in the position A₁'.
Then let C₁' be the point which is behind A' by Iṣṭa-nāḍīs
so that C₁' the diametrically opposite point C₁ is far ahead
of B in stead of preceeding it. This means that the star
which should first set heliacally and then after a few days
rise heliacally, is now in such a position that it is to rise
heliacally even before setting heliacally. This is an un-
tenable position. That this is not tenable may be seen
otherwise. The diametrically opposite point of Astalagna
ie. the point C of the ecliptic which should set along with
the planet should have a longitude less than that of the