On this day in 1604 Johannes Kepler began systematically observing a new, very bright star that had abruptly appeared in the constellation Ophiuchus. For three weeks, the star outshone all other heavenly bodies save the Sun, the Moon and Venus. The star was even visible during the day. We now know that the star was a supernova, the most recent one to have exploded in our own galaxy. The drawing is Kepler’s own of the new star (the star is marked N on the right ankle of Ophiucus, the serpent bearer). The image shows (in false color) the infrared emission from supernova remnant; it was made by NASA’s Spitzer Space Telescope four centuries after the supernova first appeared in the sky.