JF Ptak Science Books Post 1977
It seems to me that in the history of astrology--or at least for what seems to be most of it, at least through the late antiquarian publishing aspect of it--that comets and meteors were basically not utilized. Perhaps it was because in that world these entites didn't really effect anything--perhaps they were simply mysterious, spurious, and incongruent, and not a subject for installation in the astrological night sky. Comets (from the Greek, kometes, "long-haired") and meteors (Greek again, from meteoran, a "thing in the air") and bolides (exploding meteors, from the Greek bolis, or "missile"), holosiderites, siderolites, aerolites uranolites, and so on, have a long and complex story in the history of astronomy, at least in some ways; perhaps the most influential thinker on comets held thinking at bay and did so for two milennia: Aristotle's Meteorology made the case that comets were not a planet or associated with planets or even necessarily part of the heavens--rather they were a phenomena of the atmosphere. So perhaps their use as astronomical/astrological objects was limited by their very Aristotlean obviousness of being near-Earth objects.
The Comet of 1066 (later named Halleys' Comet), as depicted in the Bayeux Tapestry (completed in the 1080's)
The fear aspect of comets--the Comet of 1528--was depicted in Ambrose Pares Livres de Chirurgie (1597), and shows what part of the concern was (the coming demise of nations, the death of rules) with the appearance of decapitated heads and a large sword and raining daggers:
The night sky is a mnemonic device, a place to store memory and a holder of the alphabet of myths and beliefs of all, a culture written large across the sky. Meteors and comets were not predictable, and could add nothing insofar as a consistent bit of storytelling was concerned, though they certainly created their own stories in each observed appearance; they could also add punctuation and exclamation to whatever constellation they appeared in. For example if one appeared in a juncture with Jupiter, a major event for royalty would possibly be foretold. But as a permanent element to the visualization of the night sky, they had little power even though they seemed to be displays of fantastic energy and power in themselves.
[For some reason the celestial court, divided by sunlight and flanked by two other sources of light, have ofund it expedient to issue comets from the mouths of Heaven Canon. I'm not sure what's going on in the forground with the fellow working his spade next to the triangular blankness. the man to his right seems to have been overtaken in fear (as have the group of people visible to the left over the shoveler's shoulder).]
[Halley's comet appears again on the title page of this work by the Hungarian George Henischius, a professor of rhetoric, mathematics and medicine at Augsberg.]