The prodigious halo of the other Huygens
Published in Appl. Opt. 54 B185-B193 in 2015
G.P. Können
At the height of the ceremony in the Principality of Orange of the restoration of the sovereignty of the House of Nassau in 1665, a ceremony led by Christiaan’s father, Constantijn Huygens, a “solar crown” appeared in the sky, apparently a divine sign of approval. A nearly forgotten contemporary color engraving of this miraculous event has survived. Constantijn seized the opportunity by using to his advantage the general euphoria among the citizens caused by the appearance. We argue that Constantijn knew exactly what was going on in the sky because of his son’s work on halo theory. Given its brightness and its time of appearance, it seems plausible that the most prominent halo in the Orange halo display was a circumscribed halo rather than the more familiar but bleaker circular 22° halo. The same probably holds for most of the other high-sun halos that caused general consternation, dating from the Octavian halo of 44 BC, to the Chernobyl halo of 1986, and indeed up to bright high-sun halos of the present.