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

411 V are congruent because AZ = A'Z and ZV is common ∴ AV = VA'. But AV + VA' = 180° because the Ecliptic and the horizon being two great circles, they bisect each other. Hence AV = 90°. Then a celestial body situated at V will be depressed along ZV the vertical, say, to a point B. Let ☉ be any arbitrary position of the Sun; then ☉ will be depressed along the vertical Z☉, say, to a point C. Draw CD perpendicular on the Ecliptic. Then ☉D is the component of the parallax ☉C along the Ecliptic where as DC is its component perpendicular to the Ecliptic. Thus ☉D is the parallax in longitude and DC is the parallax in latitude. The word ‘Lambana’ means etymologically लम्बते अनेनेति लम्बनम् ie. that amount by which the celestial body is depressed (along the Ecliptic). In Hindu Astronomy the word Lambana is applied to parallax in longitude alone whereas the word Nati is applied to parallax in latitude. Hence to translate Lambana as parallax alone is not correct. The word Drik-lambana is applied to mean parallax along the vertical, and the word Sphutalambana is occasionally used to connote parallax in longitude. As Bhāskara rapidly comments on the verses in this Gaṇitādhyāya, he having dealt with the subject of parallax elaborately under the caption, Grahaṇa Vāsanā, in the Golādhyāya, to catch up his thought, we have to treat the subject first from the modern view point and then elucidate what he has said in the Golādhyāya, much matter of which is reiterated by him under the commentary here in the Gaṇitādhyāya. (Ref. Fig. 91) From the △EAM, (sin EMA) / a = (sin EÂM) / d = (sin ZÂM) / d where a is the radius of the Earth and d the distance of the celestial body (here the Moon)