CASSIOPEIA, in Astronomy, one of the constellations of the northern hemisphere, situated next to Cepheus. In 1572, there appeared a new star in this constellation, which at first surpassed in magnitude and brightness Jupiter himself: but it diminished by degrees, and at last disappeared, at the end of eighteen months. It alarmed all the astronomers of that age, many of whom wrote dissertations on it; among the rest Tycho Brahe, Kepler, Maurolycus, Lyceus, Cramineus, &c. Beza, the landgrave of Hesse, Rosa, &c. wrote to prove it a comet, and the same which appeared to the Magi at the birth of Jesus Christ, and that it came to declare his second coming; they were answered on this subject by Tycho. The stars in the constellation Cassio-
peia, in Ptolemy's catalogue, are 13; in Hevelius's, 33; in Tycho's, 46: But in the Britannic catalogue Mr Flamstead makes them 55.