The practical astronomer : comprising illustrations of light and colours, practical descriptions of all kinds of telescopes, the use of the equatorial-transit, circular, and other astronomical instruments, a particular account of the Earl of Rosse's large telescopes, and other topics connected with astronomy (1845)
Dick, Thomas, 1774-1857 · London : Seeley, Burnside, and Seeley · leaf 174
lections theexterior bow becomes faint and ill-defined incomparison of the interior or primary bow. Inthis case the upper part of the secondary bow willnot be seen when the sun is above 54° 10 abovethe horizon ; and the lower part of the bow willnot be seen when the sun is 60° 58 above thehorizon.… … ing to represent all the different colours—let ussuppose only three drops of rain, and three dif-ferent colours, as shown in the figure. The spec-tator O being in the centre of the two bows, hererepresented,—the planes of which must be con-sidered as perpendicular to his view—the dropsA,B, and C…
Astronomy · Astronomical instruments · Telescopes
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