CASSIOPEIA, in Astronomy, a constellation in the northern hemisphere, situated near to Cepheus. In 1572 there appeared a new star in this constellation, which in magnitude and brightness surpassed even Jupiter; but it diminished by degrees, and it had at the end of eighteen months disappeared. Several astronomers of that age, as Tycho Brahe, Kepler, Maurolycus, Lyceus, and Gramineus, wrote dissertations on it. Beza the landgrave of Hesse, Rosa, and others wrote to prove it a comet, affirming that it was the same which had appeared to the Magi at the birth of our Saviour, and that it came to declare his second coming. On this subject they were answered by Tycho.