The Astronomical Observatories of Jai Singh c21.s3: C. (4) Climates and Longest days
The Astronomical Observatories of Jai Singh c21.s3
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C. (4) Climates and Longest days
c21.s3.1
| Climates. | Hours of longest day. | Latitudes. | | | | | Longest Days. | |
| | | After Ptolemy. | Al-Battāni.¹ | On Jaipur A Astrolabe. | Calculated from hours. | | Calculated from latitudes. | |
| | | | | | | | Latitudes. | H. M. |
| First . . . . | { 12½ 13 | 12° 30' 16° 27' | .. 16° 39' | 12° 43' 16° 44' | .. 16° 43' | | 20 21 | 13 13 13 17 |
| Second . . . | { 13¼ 13½ | 20° 14' 23° 51' | 20° 28' 24° 5' | 20° 31' 24° 10' | .. 24° 10' | | 22 23 | 13 21 13 25 |
| Third . . . . | { 13¾ 14 | 27° 12' 30° 2' | 27° 28' 30° 40' | 27° 34' 30° 46' | .. 30° 46' | | 24 25 | 13 29 13 34 |
| Fourth . . . | { 14¼ 14½ | 33° 18' 36° 0' | 33° 37' 36° 22' | 33° 43' 36° 28' | .. 36° 28' | | 26 27 | 13 38 13 42 |
| Fifth . . . . | { 14¾ 15 | 38° 35' 40° 56' | 38° 54' 41° 15' | 39° 1' 41° 21' | .. 41° 21' | | 28 29 | 13 47 13 52 |
| Sixth . . . . | { 15¼ 15½ | 43° 41' 45° 1' | 43° 25' 45° 22' | 43° 30' 45° 39' | .. 45° 32' | | 30 40 | 13 56 14 51 |
| Seventh. . . | { 15¾ 16 | 46° 51' 48° 32' | 47° 12' 48° 53' | 47° 38' 48° 59' | .. 48° 59' | | 50 60 | 18 10 18 31 |
| | 16½ | 50° 4' etc. | .. | .. | .. | | .. | .. |
c21.s3.2
¹ Opus Astronomicum, Ed. Nallino, 2nd part, 65—66.
c21.s3.3
The calculated results are obtained from the formula 180°+2h / 15 = the longest day, where sinh = tan φ . tan ω and where ω=23° 29', and φ=the latitude.