How quickly does a supernova happen?

How long does it take for a star to explode in a supernova? How long will it take before we know it has exploded? - Quora

Imagine the Universe!

Astronomers document a not-so-super supernova in the Milky Way

NASA's Roman Mission: Using Exploding Stars to Solve the Biggest Cosmic Mysteries

ESO Supernova Exhibition — How dangerous are supernova explosions?

Supernova, Definition, Types, & Facts

A Star Went Supernova in 1987. Where Is It Now? - The New York Times

How Quickly Does A Supernova Happen? The Stunning Speed of a Core Collapse Supernova

What is a supernova? - Space Center Houston

What Will a Betelgeuse Supernova Look Like From Earth?

A Star Threw Off a Sun's Worth of Material. And Then it Exploded! - Universe Today