The year 1604 in science and technology involved some significant events.
Astronomy
9 October – The supernova which becomes known as Kepler's Supernova (SN 1604) is first observed from northern Italy. From 17 October, Johannes Kepler begins a year's observation of it from Prague. As of 2006[update], this is the last supernova to be observed in the Milky Way, and the last visible by the naked eye until 1987.[1][2]