Kepler's Supernova blazed into view over Europe
On this day · 9 October 1604
The last supernova seen with the naked eye in our galaxy outshone every star — and even rivaled Jupiter.
On October 9, 1604, a brilliant new star appeared in the constellation Ophiuchus, spotted by observers across Europe before clouds and bad weather kept the astronomer it would be named for from seeing it until October 17. When Johannes Kepler finally got his look, he began a careful study that he published in 1606 — earning the exploding star the name Kepler’s Supernova, formally SN 1604.
At its peak the supernova shone brighter than Jupiter and remained visible to the naked eye for roughly 18 months, even glimpsed in daylight. Modern astronomers classify it as a Type Ia supernova: the thermonuclear detonation of a white dwarf.
It remains the most recent supernova observed with the unaided eye inside our own Milky Way.
Nothing since has matched it within our galaxy. The next naked-eye supernova, SN 1987A, erupted in a neighboring satellite galaxy — leaving Kepler’s star, four centuries on, still holding the record.
Sources & references
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