Johnson has reviewed an English translation of the German text and compared the woodcut to known astronomical phenomena to determine that it represents a secondhand depiction of a particularly gaudy sundog, a phenomenon formed when sunlight is scattered through the sky thanks to the prism effects of atmospheric ice. The characteristic arcs seen in the woodcut are indicative of sundogs, which also can generate colored orbs and shadowy, angular lines, as Johnson demonstrates.
The clincher is his collection of other sixteenth century broadsheets depicting known astronomical phenomena in rather odd ways, such as a rain of fire meant to represent an aurora. Thus, in context the 1561 image fits into these artistic depictions of astronomical phenomena.
Mystery (apparently) solved.
(Read Johnson's blog post here.)