I wasn't able to open the web site, but I've heard of the event. There was another event of the same magnitude in June of 1054. It was documented in China and Japan and can be seen in cave paintings in Australia. Here's the thing that I find intriguing thing - Nobody in Europe saw a darn thing!!! That's right. It blazed for 23 nights AND DAYS! That's right, it was so bright it was visible during the daytime in the then-undiscovered "New World", yet nobody in Europe saw it? We can pin-point the date that it was first observed, July 11th, 1054, because Arabic Calendars were very sophisticated. They coroborate the sightings in the Orient. From what Historians can gather, it had a magnitude of at around -10, approaching the brilliance of a Full Moon. Then, on the night of August 2nd, it faded from view even faster than it had appeared. It is mentioned in the verbal legends of Alaska and Polynesia, Primitive Cultures at the time, but nothing in European History speaks of it.
Today we know the event took place, we can "see" the remnants of a Supernova in the Constellation of Taurus, but there's nothing in Ancient European Literature that even mentions it.

An Age is not called "Dark" because light doesn't shine, my friends, but because people refuse to see it.