aberration. By the known motion of the earth in its orbit, we have thevalue of A B corresponding to one second of time: we havethe angle A D B by observation: the angle at B, is a rightangle, and (from these data) computing the side BD wehave the velocity of light, corresponding to one second… … * 0 270 *To obtain the logarithmetic tangent of 20\36 see note on page 128. 15 216 ASTRONOMY. Chap. vii. in one second of time, is within a very small fraction of 19miles; the logarithm of the distance is 1.278802, and, fromthis, we find that BD must be 192600 miles, the velocity oflight in a…
Astronomy
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![An illustration from Nicolai Copernici Torinensis De reuolutionibus orbium coelestium, libri VI : Habes in hoc opere iam recens nato, & aedito, studiose lector, motus stellarum, tam fixarum, quàm erraticarum, cum ex ueteribus, tum etiam ex recentibus obseruationibus restitutos: & nouis insuper ac admirabilibus hypothesibus ornatos. Habes etiam tabulas expeditissimas, ex quibus eosdem ad quoduis tempus quàm facillime caculare poteris. Igitur eme, lege, fruere. [Line in Greek] (1543)](https://img.insideoutlibrary.com/img/200/ia-nicolaicopernici00cope-322-213.webp)
