Ephemeris

Bright Lights in Sky

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The chart above shows the zodiac, the band of the sky in which the sun, moon, and planets move. The chart is oriented as if you were looking to the south from somewhere in the northern hemisphere. If you look carefully you may even be able to recognize some of the stars or constellations in the chart.

If you look real carefully there's a diagonal gap in the starfield, it's a programmer error.

The symbols superimposed on the chart show the locations of the sun, moon, planets, and the 12 signs of the zodiac. The English name for each of the symbols used above is given in the table to the left along with the position calculated or the defined position of the signs of the zodiac.

The accuracies of the positions are a fraction of an arc minute for the sun and inner planets, an arc minute for the outer planets, and two arc minutes for the moon. 1000 years from the present, these formulae will have additional errors on the order of 2 arc minutes for the sun and planets, and 7 arc minutes for the moon.

The positions are computed in JavaScript according to formulae described by Paul Schlyter in computing planetary positions. He disagrees with my choice of ecliptic coordinates, preferring equatorial, but I find it easier to track the moon and planets along the ecliptic.

This web page is dedicated to the memory of Raphael Benitez.