I have an earlier answer that might interest you!

• What did people believe the Crab Nebula in 1054CE was, and what were the reactions to it suddenly becoming visible in the sky?

1054 is not the days of YouTube reaction videos and live-tweeting Game of Thrones episodes. Anyone writing something down was necessarily the elite, interpreting events in their own rareified context and out of their own educational backgrounds. It's also really interesting to note that in the case of the 1054 supernova, two of the key records (Japan and Cairo/Constantinople) actually date from 200 years after the event. That is to say: we aren't necessarily dealing with a "reaction" on the part of the immediate author, but a longer-term and more considered interest.

Chinese astronomers (therefore also astrologers) had been observing "extraordinary stars," as Joseph Needham put it, for centuries and possibly millennia even before 1054. He suggests the earliest known record comes from a set of oracle bones dated around 1300 BCE. One gives a specific month and day on which a "great star" or "fire star" (I don't read Chinese, and it looks to me like there is one translation in the text and another in the footnote?) appeared; the other has a date two days later than that and notes that "the great star dwindled." By the Han dynasty, however, comets and novae were commonly enough observed and discussed by astrologers to have acquired a set name that would be used for centuries: "guest star."

For 1054, Needham quotes the account from the Song Hui Yao, produced at the Song Chinese court, that contains all the standard pieces of astronomical phenomena descriptions: timing of appearance, duration, color and brightness, location, and prognostication value.

In the fifth month of the 1st year of the Chih-Ho reign-period, Yang Wei-Te said, 'Prostrating myself, I have observed the appearance of a gueststar; on the star there was a slightly iridescent yellow colour. Respectfully, according to the disposition for emperors, I have prognosticated, and the result said, "The guest-star does not infringe upon Aldebaran; this shows that a Plentiful One is Lord, and that the country has a Great Worthy." I request that this prognostication be given to the Bureau of Historiography to be preserved.

Nearly two years later, the dwindling and disappearance of the guest-star was described as an omen for the departure of guests from court.

This is a great example of the importance of the recorder's context. We're dealing with a courtly writer and a courtly astronomer producing a text at the royal court; no wonder the event's meaning will pertain to the emperor. And these are also people trained in astronomy/astrology, with established traditions (judging by the existence of "genre standards" for guest-star reports) of whether to draw meaning and, if so, what kind of meaning to draw.

Another of the Chinese sources will illustrate this point nicely. The Qidan Guozhi was written in the 13th century by a Song author looking back on the northern Liao dynasty/Khitan Empire. It mentions the 1054 supernova but offers a different link between stars and life: it was a portent of the Liao emperor's death in the coming year.

The Japanese source likewise postdates the event by a lot. Fujiwara no Teika (1162-1241) was an aristocratic courtier and poet who is best known to us for keeping a wonderfully gossipy diary. In addition to the hearsay of his day, he included plenty of legends and anecdotes he'd heard or read about the past. He uses the Japanese equivalent of "guest-star" to describe an astronomical event recorded as occurring either one week or one month plus one week before the Chinese record asserts.

Teika's account doesn't include an astrological interpretation of the guest-star itself--and why should it? He's writing a diary 180 years after the fact. Instead, we look to his context. And there it is: that same year, a "guest-star" scholars are pretty sure was a comet had blared through the sky. Fascinated, Teika dove into archives and dug up a long list of earlier accounts of guest-stars.

I've saved the Arabic account for last because it's my favorite. Not for the words itself, but for how much insight into the diverse, multicultural Middle Ages it gives. This is (surprise, surprise) yet another after-the-fact recording. It's from a mid-13th century biographical dictionary of medical experts. This was a very popular genre of history writing in the medieval Arab world. And where the eminent figure was an author, the biographer/compiler might well include an anecdote in the subject's own voice (accurate or not).

This is the case for the Uyun al-Anba and one of its 11th century subjects, Al-Mukhtar Ibn Butlan. What makes this so exciting is that Ibn Butlan was not just a renowned physician but a Christian, who seems to have moved between Cairo and Constantinople while obviously retaining his fame among the Arab intelligentsia and his social ties in both places. So goes the anecdote:

I, Ibn Abi Usaybi'a, have copied the following from an account in [Ibn Butlan's] own hand. He says, "One of the well-known epidemics of our time is that which occurred when the spectacular star appeared in Gemini in the year 446/1054. In the autumn of that year fourteen thousand people were buried in Constantinople. As this spectacular star appeared in the sign of Gemini which is the ascendant of Egypt, it caused the epidemic to break out in Old Cairo when the Nile was low, at the time of its appearance.

...Ibn Butlan, the doctor, links an astronomical event to disease outbreaks. Shocking!

~~

If you want to read more about the cool parts of the Middle Ages, you can check out my book How to Slay a Dragon: A Fantasy Hero's Guide to the Real Middle Ages! Whether you're dealing with finding an inn in Cairo, a sea-monster who just bit a chunk out of your hull in the English Channel, or just your standard, everyday haunted public toilets--medieval history has the answers you seek.