Colbert, E[lias] [from old catalog] · Chicago, G. & C. W. Sherwood · leaf 86
uinoctial is 12 hours above the earth, and12 hours below it; the passage from the horizon tothe meridian being measured by 6 hours, or (itsequivalent) 90° of a great circle. 130. In the accompanying diagram let N Srepresent the horizon ; P the North Pole, elevatedabove the horizon by an amount… … horizon. The angle E P A is equal to 90°; thatis, a star at E would arrive at A in 6 hours after-wards. A meridian circle through the star at T,would cut the Equinoctial at D ; and the Arc E D,measured by the angle E P D, is the excess over90° of the angle APD. In the spherical triangleE D T, we…
Astronomy · Stars
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