420 Years Ago: Astronomer Johannes Kepler Observes a Supernova

In October 1604, a new star appeared in the sky, puzzling astronomers of the day. First observed on Oct. 9, German astronomer Johannes Kepler (1571-1630) began his observations on Oct. 17 and tracked the new star for over a year. During that time, it brightened to magnitude -2.5, outshining Jupiter, and for several weeks remained […] Read more