It’s difficult to imagine what the world saw in the spring of 1006, but we can experience a sort of astronomical flashback through the “constellation” of sixty-six satellites operated by Iridium Satellite LLC. Each satellite maintains its orientation to the Earth’s surface in such a way that the Sun predictably glints off its highly reflective antennas.
For ground observers located near the center of a Sun reflection, the satellite briefly flares from invisibility to brilliance and then quickly fades out. At peak brightness, Iridium flares can match and even exceed the eleventh-century supernova. Individual flares can be seen only over an area of a few tens of miles, but web sites and computer programs specializing in satellite observation offer Iridium flare predictions for specific locations (for example, see HeavensAbove.com).
Anyone pondering the appearance of the next visual supernova should see at least one Iridium flare.