Definition
The phrase “Comet of 841–842” refers to a purported celestial object—a comet—reported to have been visible during the years 841 and 842 AD. No widely accepted or standardized astronomical designation for this object exists in contemporary scholarly literature.
Overview
Historical chronicles from the early medieval period, particularly East Asian annals such as the Jiu Tang Shu (Old Book of Tang) and various European monastic records, contain occasional references to an unusual “guest star” or comet observed around the early 840s. These accounts are fragmentary and vary in detail, making it difficult to confirm whether they describe a single cometary event spanning both years or multiple separate sightings. Modern astronomical catalogues do not list a distinct comet for this period, and the object has not been assigned a systematic name (e.g., a designation from the International Astronomical Union).
Etymology / Origin
The term is a straightforward descriptive label constructed from the English words “comet” and the dating range “841–842,” indicating the years in which the phenomenon was reportedly observed. It does not derive from a historical proper name or a specific cultural designation.
Characteristics
Accurate information is not confirmed. The surviving medieval descriptions are vague, typically noting a bright, moving point of light in the sky, sometimes accompanied by omens or portentous interpretations. No reliable measurements of its brightness, orbital parameters, tail length, or duration are available. Consequently, scientific characterization of the object (e.g., orbital period, composition) remains undocumented.
Related Topics
- Historical comets – documented cometary appearances in antiquity and the Middle Ages (e.g., Halley’s Comet, the Great Comet of 837).
- Medieval astronomical records – chronicles and astronomical treatises from the 9th century that sometimes mention “guest stars.”
- Astronomical nomenclature – modern practices for naming and cataloguing cometary bodies.
Note: Due to the paucity of reliable primary sources and the absence of the comet from recognized astronomical databases, the “Comet of 841–842” is not considered an established concept in contemporary astronomy.