The Astronomical Observatories of Jai Singh c7.8

c7.8

⁵ In figure 25, PP¹, are the poles of the equator, K¹ is a pole of the ecliptic, and Pr. P¹ is the equinoctial colure. The centre of projection is ♁ and pc q p¹ is a half of the projected solstitial colure. In the figure circles of declination, etc., are drawn for angles of 30°, 45°, and 60°. D₁D₁, D₂D₂ and D₃D₃ are circles of declination. pA₁ p¹, pA₂p¹, pA₃p¹ are circles marking right ascension; similarly L₁L₁, L₂L₂, L₃L₃ are circles of latitude, and l₁K₁, l₂k₁, l₃k₁ circles of longitude. On the instrument itself circles of declination and latitude are drawn for every degree, and those for right ascension and longitude for every three degrees. The latitudes and declination circles are numbered from the centre to the poles; the ecliptic is marked with the signs of the zodiac from O to F (figure 21), and back again from F to O, and similarly along the other half of the ecliptic line, and each sign is graduated for every three degrees; the graduations on the equator commence at D and proceed on the north side of the line to B which is numbered 180, and then the graduations are continued on the south side of the line ending up at D, which is this time numbered 360.