Tycho Brahe on the comet of 1577. 17th-century diagram of the orbit of the comet of 1577, as described by Danish astronomer Tycho Brahe (1546-1601). The smaller circle is the orbit of the comet around the Sun, and the larger circle is the orbit of the Sun around the Earth. Tycho devised his system to account for his observations of the comet's orbit: the Sun and Moon orbit the Earth, while the planets and the comets orbit the Sun. The Great Comet of 1577 was so bright that it was visible during daylight. This page is from the 1603 edition of Tycho's 'De Mundi Aetherei Recentioribus Phaenomenis Liber Secundus', originally published in 1588.