Comets, novas and the Mayans — Science News, June 30, 1973
Did the Mayans record novas and comets? … Comparing dates of known historic novas and comets with  Mayan dates, [a researcher] found no acceptable correlation. Nevertheless, [the researcher] believes that the Mayans probably did record such events and that a record will eventually be found.
Solid evidence that ancient Maya people marked dying stars or passing comets continues to elude archaeologists. Several early codices and stones may have recorded hieroglyphs that together mean “comet.” But Spanish conquistadores destroyed many of the originals, and only copies made well after the Maya empire’s collapse clearly depict comets.
In 2017, an analysis of Maya records and astronomical data hinted that the Maya indirectly marked at least one comet by predicting when meteor showers would dazzle the sky. Between the years 250 and 909, six royal coronations happened within days of the annual Eta Aquariid meteor shower, researchers found, which occurs when Earth passes through the tail of Halley’s comet.