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

259
Fig. 43
This formula gives not only the meridian zenith
distance but H sine of the zenith-distances of the Sun
when he is on the Koṇa-Vṛtta or prime-vertical or
unmaṇḍala.
Comm. From fig. 43, H sin z = SM = LE₁ = E₁s −
sL = R − H versine (Ss) = R − H versine (altitude) as
given. Since R − H versine (altitude) = R − {R −
H cos (90 − z)} = R − (R − R sin z) = H sin z, so this
formula applies wherever the Sun be. This is almost
begging the question as H sine of z is being sought
through H versine of (90 − z).