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Astronomical "transients" are objects that occur in the sky and vanish after a while. They are visible only for a period of time. 

Modern astronomers classify them as: 

  • comets (objects of the solar system) 

  • stellar transients

    • eruptions on surfaces of stars (novae, variable stars)

    • explosions of stars (supernovae, mergers)

but ancient astronomers did not know what they were seeing: for them, they were miraculous appearances. ​

Aristotle, Lucretius and Seneca mentioned some comets in combination with earthquakes, waves and other phenomena on Earth but no stellar transients. In a fruitful collaboration, two other projects revisited many records of transients in chronicles -- most of them originating in Old China and its colonies because of their usage of the "guest stars" for political omens.

These projects were:

  • Centro de Astrofísica, Universidad de Valparaíso, Chile: financial support by FONDECYT regular No. 1170566

  • Applied and Computational Historical Astronomy, Michael-Stifel-Center Jena, Germany - funded by the Free State of Thuringia and University of Jena, Germany

Comets in Antiquity


​Editions and Translations used

  • Louis, P. (1982) Aristote. Météorologiques, tom. I & II, Paris: Les Belles Lettres.

  • Hine, H. M. (1996) L. Annaei Senecae Naturalium Quaestionum Libros, Stuttgart / Leipzig: Teubner.

  • Godwin, J. (1991) Lucretius De Rerum Natura VI, edited with translation and commentary, Warminster: Aris & Phillips Ltd.

Great Comet 
winter 373 / 372 BCE

Aristotle mentions this comet in connection with weather phenomena.

Aristotle, METE I 6.343a35-b6:

Moreover the statement that a comet only appears in the north, with the sun at the summer solstice, is not true either. The great comet which appeared at the time of the earthquake in Achaea [1] and the tidal wave rose due west [apo dusmōn tōn isēmerinōn[2]; and many have been known to appear in the south. Again in the archonship of Euclees, son of Molon, at Athens [3] there appeared a comet in the north in the month Gamelion [January/February], the sun being about the winter solstice.



Cf. Seneca, NQ VI 23.4:


This Callisthenes, in the books where he describes the inundation of Helice and Buris,[4] and the event that drove them into the sea, or the sea onto them, says what has already been said in an earlier section: […]

"According to Strabo (VIII 7), this earthquake (which was also felt at Delphi where the temple of Apollo was destroyed) took place two years before the battle of Leuctra, therefore in 373, when Aristotle was ten years old: it buried the city of Boura and the subsequent tidal wave took Helice away. This catastrophe had strongly struck the spirits: Aristotle speaks about it again at 368b6." English translation of the comment found in the edition of Louis.

"The equinox setting indicates the direction due west. The comet in question is perhaps Halley's Comet, which reappears on average every 75 years and may have been visible around 373 BCE." Engl
ish translation of the comment found in the edition of Louis.


At 427/6 BCE according to Louis.

"Helice and Buris (also called Bura) were towns in Achaea, on the south of the Gulf of Corinth. See FGH, 124F19." Comment found in Hine (2010).



Seneca, NQ VII 16.2.4-3.6:


Ephorus is not someone of the most scrupulous reliability: he is often deceived, more often he deceives, as in the case of this comet, which was watched by the eyes of all humankind, because it brought about the occurrence of a major event, drowning Helice and Bura at its appearance. He says it separated into two stars; but apart from him no one has reported this. Who could have observed that moment at which the comet broke up and was reduced to two pieces? How come, if there is somebody who has seen a comet being split in two, that nobody has seen one forming from two stars? Why did he not add what stars it divided into, since it must have been some of the five stars?

Lexicon of Stellar Transients
(some examples)

Stellar Transiens

​Editions, Translations and Selections used

  • Clark, D., & Stephenson, F. 1977, The Historical Supernovae, Oxford (Pergamon).

  • Hertzog, K. P. 1986, Observatory, 106, 38.

  • Ho, P. Y. 1962, Vistas Astron., 5, 127.Pskovskii, Y. P. 1972, Soviet Astron., 16(1), 23.

  • Hsi, T.-T. 1957, Smithonian Contributions to Astrophysics, 2, 109.

​Editions, Translations and Selections used

  • Stephenson, F. R., & Green, D. A. 2002, Historical Supernovae and their Remnants, Oxford University Press (New York)

  • Xi, Z.-Z., & Po, S.-J. 1966, Science, 154(3749), 597.

  • Xu, Z., Pankenier, D.W., & Jiang, Y. 2000, East Asian Archaeoastronomy, Gordon and Breach Science Publishers (Amsterdam).

Guest Star 369 CE

Translations from Chinese chronicles:

"Zigong" is the constellation of the Purple Palace, a huge area in the sky, almost the whole circumpolar region. The "west wall" of this palace-constellation is a well-defined chain of star.

Suggested Identifications


Supernova remnants (SNRs, red) and pulsars (PSRs, blue) in the area or "the west wall of Zigong"


Cataclysmic variables (CVs, green) and nebulae classified as "planetary nebulae, PNe" in the area of "the west wall of Zigong":

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