The Astronomical Observatories of Jai Singh c6.s1.t1.54

c6.s1.t1.54

¹ See Book ii of the Almagest; al-Battānī, Opus Astronomicum, 2nd Part, p. 65f; the Sūrya Siddhānta, ii, 60f. etc.; also the note on astrology (Appendix B). From the formula Sin a₁ = tan φ . tan δ, where φ is the latitude and δ the declination, the so-called ascensional differences are calculated; then from sin b₁ = sin 30°. cos ω / cos δ₁, sin (b₁ + b₂) = sin 60°. cos ω / cos δ₂, sin (b₁ + b₂ b₃) = 1 the values of b are calculated; and finally t₁ = b₁ - a₁, t₂ = b₂ - a₂ + a₁, t₃ = b₃ - a₃ + a₂, t₄ = b₄ - a₄ + a₃ = b₄ + a₃ - a₂ and so on, since b₄ = b₂, b₅ = b₁, b₆ = b₁, and a₅ = a₅ = a₁.