I’ve always wondered how long the flare of a supernova lasts. There is, of course quite a bit of variation but the brightest part of this one, that occurred during our own Cretaceous Period, lasted from the beginning of March to the end of June 2015.

Video Credit & Copyright: Changsu Choi & Myungshin Im (Seoul National University)

Explanation from Astronomy Picture of the Day:

The actual supernova occurred back when 80 million years ago, but images of the spectacular event began arriving last year. Supernova 2015F was discovered in nearby spiral galaxy NGC 2442 by Berto Monard in 2015 March and was unusually bright — enough to be seen with only a small telescope. The pattern of brightness variation indicated a Type Ia supernova — a type of stellar explosion that results when an Earth-size white dwarf gains so much mass that its core crosses the threshold of nuclear fusion, possibly caused by a lower mass white-dwarf companion spiraling into it. Finding and tracking Type Ia supernovae are particularly important because their intrinsic brightness can be calibrated, making their apparent brightness a good measure of their distance — and hence useful toward calibrating the distance scale of the entire universe.