On January 25, 2014, I asked my grandson, who was visiting that night, if he'd like to see a supernova "in progress" in a distant galaxy. I had heard a few days earlier that a supernova had "gone off" in the Irregular Galaxy M82, also called the Cigar Galaxy. He was clearly interested, so we took the image you see below on the left.
Of course, for an untrained eye, he didn't really see anything unusual in that image. So I told him what professional astronomers do. They find an image of the same galaxy taken at least months before and compare the two images. Well it turns out that I had taken an image of M82 in April 2012. That's the one below on the right. So when we compared the images together, he and I could see that very bright "dot" in the fuzzy left end of the galaxy in the left-hand image. It is not in the April 2012 image. That is supernova 2014J or often written SN2014J. (J is the 10th letter in the alphabet, and this SN was the 10th one discovered in the year 2014.