Bøger af Bryant Tuckerman

These tables for A.D. 2 to A.D. 1649 are an extension, with some improvements, of earlier ones for 601 B.C. to A.D. 1. As before, they give the geocentric positions (tropic celestial longitudes & latitudes, i.e. with respect to the mean equinox of date), in units of 0 degrees.01 for the Sun & planets, & 0 degrees.1 for the Moon, at 16h Universal Time - 4 P.M. Greenwich Civil Time - 7 P.M. local mean time of 45 degrees East longitude (Babylon), on the indicated dates, all in the Julian calendar, hence for Julian dates 5n + 1/6 for the Moon, Mercury, & Venus, & 1-n + 1/6 for the Sun, Mars, Jupiter, & Saturn. The same adaptation of the theories of Leverrier, Gaillot, & Hansen, with modified elements by Schoch, was used as before, except as noted below. The chief change has been to improve the positions of Jupiter & Saturn. Tables.

The need for these tables became pressing when hundreds of astronomical cuneiform tables in the British Museum became available for study, partly through the copies made in the 1880s and 1890s. All these texts originally came from some archive in Babylon which was discovered by Arabs in the middle of the 19th century. Most of the texts were written from about 330 B.C. to the first century A.D. Many of the texts are fragments of the original clay tables which have broken. In many cases, a fragment contains only parts of a few legible lines. Much of the information is of an astronomical character. It is evident that for investigations of these tablets the possibility of rapid scanning of accurately dated planetary positions is of primary importance.