To say that Victor Buso was in the right place at the right time may be the biggest understatement in the history of stargazing.
By pure luck, the amateur astronomer from Rosario, Argentina snapped the first before-and-after images ever captured of a star as it explodes in a brilliant flash of light and morphs into a supernova.
Astronomers call this pivotal moment "shock break-out," and have dreamt for decades of witnessing such a stellar metamorphosis in real time.
Melina Bersten, a scientist at the La Plata Astrophysics Institute in Argentina and lead author of a study in journal Nature that describes the discovery, put the odds of stumbling across it at up to 1 in 100 million.
"Professional stargazers have long been searching for such an event," said Filippenko, who followed up from the Lick Observatory near San Jose, California. "Observations of stars in the first moments they begin exploding provide information that cannot be directly obtained in any other way."
The new data provide key clues, for example, about the physical structure of the star just before its catastrophic demise, as well as the nature of the explosion itself. It was also an opportunity for scientists to conduct reality checks.
"For the first time, this fortuitous discovery allows astronomers to test the validity of their models on real data," co-author Federico Garcia, an astrophysicist at Paris Diderot University, told AFP.
"It was a great feeling when I saw the images," he added.
Analysis of the event showed that the SN 2016gkg is a Type IIb supernova, emerging from a massive star that has lost most of its hydrogen envelop before it explodes.