[nine_k]

This is Wikipedia. If you possess the knowledge about local calendars of the time, go on and improve the article.

For astronomical research, it's easiest when events are dated using one calendar to correlate the observations across the whole planet. No matter which calendar specifically, it just must be uniform. For cultural research, it's more important to use a local calendar and e.g. see how the supernova was related to other culturally significant events.

Also, an article written in English is bound to use the Gregorian or Julian calendar which is familiar to the readers. An article written in Arabic, or Hebrew, or Tamil, or Malay may use the respective different calendars instead, as familiar to the readers.

[owl57]

> An article written in Arabic, or Hebrew, or Tamil, or Malay may use the respective different calendars instead, as familiar to the readers.

Extrapolating from the only example I know, I wouldn't bet on it.

Before moving to Israel I knew that Rosh HaShanah (Hebrew New Year) is a public holiday and Gregorian New Year isn't, so I expected Hebrew calendar to be somewhat visible in everyday life or at least in official documents. Turns out, with the exception of holidays — to some surprise, including the decidedly secular Independence Day — it really isn't, everyone uses Gregorian.

[nine_k]

This is somehow expected when we talk about modern Israel. Maybe it would be less so when describing events of 1006 AD, if descried by contemporaneous Jewish sources.

Again, this a difference between astronomy and history points of view. In natural sciences, one would expect the now-universal units that originated in Western science: Julian calendar, SI units, times in UTC, etc. In historical and otherwise localized studies, I would expect a local / period-salient calendar, local units as reflected in the period's documents, etc. Converting these into exact modern dates and units is sometimes hard, and subject to a debate among historians.