Solar and Lunar Eclipses Familiarly Illustrated and Explained; With the Method of Calculating Them According to the Theory of Astronomy, as Taught in New England Colleges (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1845 edition. Excerpt: ...of the moon's node from that of the moon itself, is 5.9356, and the corresponding equation, obtained from table 17th, is--.0233. This applied, leaves 66.9131 for the moon's true longitude from the mean vernal equinox. CHAPTER VIII. LUNAR, OK MENSTRUAL EQUATION OP THE SUNS LONGITUDE AND NUTATION. 67. It was observed in article 2d, 'that any motion or change of motion in the earth, produced apparently a precisely similar one in the sun. Now, the earth, like the moon, revolves round the common centre of gravity of the two, and is, therefore, subject to inequalities in this motion, the same in kind as those we have been considering in that of the moon, though far less in degree, owing to the earth's greater weight, and consequently close proximity to the centre of gravity. These inequalities, small in themselves, are rendered vastly smaller in their effect upon the sun's apparent motion, by reason of the great distance of the latter. Fig. 14. Let S (Fig. 14) represent the sun, ABF the earth, E its centre, M the moon, and C the common centre of gravity between the earth and moon, about which both revolve. The distance from E to C is not far from 2970 miles, or about three-fourths of the earth's radius. It is manifest that the longitude of the sun, as seen from E, will differ from its longitude as seen from C, by the angle CSE. When the angle MES is either 0 or 180, the angle CSE will disappear, and when it is of any other size, the latter angle can be calculated: for, in the triangle CES, the two sides, CS and CE, and the angle CES are known. We assume here, that E revolves in a circle round C, keeping CE of uniform length. It is plain from the diagram, that if the longitude of the moon exceeds that of the sun, the latter will be increased by..