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

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This difference between the nature of the times was already
dealt with.
The matter of this verse appears to have been
unnecessarily complicated by Bhāskara but on careful
scrutiny it is not so ; for, the problem is to find the time
that has elapsed after the rise of the planet upto a given
time. Here the data are the given time and the corres-
ponding position of the planet not on the horizon but
elsewhere. We could not know immediately the time at
which the planet rose. To find it alone, this method of
successive approximation has to be used and there is no
other go. Had we known the position of the planet while
rising, the corresponding Prāk-Dṛk-graha could be found
exactly and as this position of the Prāk-Dṛk-graha is a
point of the ecliptic and the Iṣṭa-lagna ie. the rising point
of the ecliptic at the given moment is also a point on the
ecliptic, the time between the moments of rising of these
two points of the ecliptic could be found in sidereal
measure directly by noting the rising times of the Rāśis in
between, without an appeal to the method of successive
approximation.
Verse 4. The computation of the times of heliacal
rising and setting of a planet in contradistinction to its
rising time during a day on account of earth’s diurnal
rotation.
The times of rising and setting of a planet have been
dealt with. Now I shall tell the procedure to be adopted
in computing the times of heliacal rising and setting of a
planet. If a planet has a daily motion less than that of
the Sun, it rises heliacally in the east, and sets in the
west ; otherwise the reverse.
Comm. Take the example of the superior planets, say
that of Jupiter. Since Jupiter moves slower than the Sun,
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