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

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estimate 1581/2 × 1/51566 × 3438 = 53′ approximately. Its
modern value is about 57′ so that the Hindu estimate is
not far from truth. Here 1581 and 51566 are the values
of a and d in Yojanas according to Bhāskara.
The Hindu astronomers do not, however, proceed
exactly as we have done in the para above to obtain the
maximum horizontal parallax. Their treatment is a little
different and is as follows. Whereas according to Modern
astronomy E M̂′ A (fig. 93) is viewed as the horizontal
[चित्र: Fig. 93]
Fig. 93
parallax, in Hindu Astronomy MÊM′ or the angular
measure of the Moon’s path equal to the radius of the
Earth is taken to be the horizontal parallax. Both,
of course, mean the same as is seen from the figure.
In as much as the Hindu astronomers knew very well
what they term कलीकरण or converting linear distances
into angular measure, converting a linear magnitude equal
to the radius of the Earth namely MM′ at the lunar orbit
into angular measure, they got
MM′/EM × 3438 = 1581/2 × 1/51566 radians = 52′-42″ as the
maximum horizontal parallax.