entire year. These observations were described in his book De Stella nova in pede Serpentarii ("On the new star in Ophiuchus's foot", Prague 1606). Delle Colombe–Galileo controversy In 1606, Delle Colombe published Discourse of Lodovico delle Colombe in which he shows that the "Star Newly Appeared in October 1604 is neither a Comet nor a New Star" and where he defended an Aristotelian view of cosmology after Galileo Galilei had used the occasion of the supernova to challenge the Aristotelian system. The description of Galileo's claims is as follows: Galileo explained the meaning and relevance of parallax, reported that the nova displayed none, and concluded, as a certainty, that it lay beyond the moon. Here he might have stopped, having dispatched his single arrow. Instead he sketched a theory that ruined the Aristotelian cosmos: the nova very probably consisted of a large quantity of airy material that issued from the earth and shone by reflected sunlight, like Aristotelian comets. Unlike them, however, it could rise beyond the moon. It not only brought change to the heavens, but did so provocatively by importing corruptible earthy elements into the pure quintessence. That raised heaven-shattering possibilities. The interstellar space might be filled with something similar to our atmosphere, as in the physics of the Stoics, to which Tycho had referred in his lengthy account of the nova of 1572. And if the material of the firmament resembled that of bodies here below, a theory of motion built on experience with objects within our reach might apply also to the celestial regions. "But I am not so bold as to think that things cannot take place differently from the way I have specified." Kepler–Roeslin controversy In Kepler's De Stella Nova (1606), he criticized Roeslin concerning this supernova. Kepler argued that in his astrological prognostications, Roeslin had picked out just the two comets, the Great Comet of 1556 and 1580. Roeslin responded in 1609 that this was indeed what he had done. When Kepler replied later that year, he simply observed that by including a broader range of data Roeslin could have made a better argument. Supernova remnant The supernova remnant of SN 1604, Kepler’s Star, was discovered in 1941 at the Mount Wilson Observatory as a dim nebula with a brightness of 19 mag. Only filaments can be seen in visible light, but it is a strong radio and X-ray source. Its diameter is