Truly greater (an atmospheric phenomenon) was that terrible comet of 1577, and in the middle of its duration, God produced another portent that was seen in the duchy of Württemburg on December 5. That day, from immediately after the sun had risen to around the hour of 10, He devised most horrible phantasms, particularly different and multicolored hats [literally: felt caps] that seemed as though they were falling onto the earth. You will not find from such stories what you would truly see looking at this comet itself, its magnitude, the brightness of its light, the rarity of its forms; yet it may be possible to compare its movements with these (stories) with certainty.
From this, it becomes clear that while the common folk viewed the portent as a sign from God, Roeslin considered it a consequence of the comet’s passage and though that by collecting and comparing such stories one could work out mathematically the comet’s exact position in space relative to the earth at any given time.
It’s interesting to contrast a scientist’s view of the events with the sensational popular view, given in the German broadsheet and repeated in a late edition of Pierre Boaistuau’s Histoires Prodigieuses (1594 ed., at 4.7), which saw the events as a message from God and a bizarre day of luminescent headwear.
At any rate, it’s interesting that the mystery-mongers like Jacques Vallée who promote the falling hats as a “wonder” in the sky (and, in Vallée’s case, have for more than 45 years) haven’t tried to find correlating texts like this one to arrive at better conclusions.