Template talk:Extract/doc

Error in documentation

The documentation states

• {{extract|juliandate|2451545}} → 1 January 2000 (Julian day 2451545 is noon 1 January 2000 UTC in the Gregorian calendar)

It would be more correct to say that Julian day 2451545 begins at, and includes, noon universal time* 1 January 2000 and continues until, but does not include, noon universal time 2 January 2000.

• Julian dates may also be used with terrestrial time, International Atomic Time, or related time scales; the scale should be stated in precise work. In precise work, using Julian dates with UTC is problematic because the meaning of a fraction of a day becomes unclear if the day comprises 86,401 seconds due to a leap second. Jc3s5h (talk) 12:35, 10 October 2019 (UTC)

Thanks for the information. I am aware that the topic is much more complex than portrayed in the documentation, and more complex than my understanding. However, as a pragmatist, I suspect that the "noon 1 January 2000 UTC" statement is close enough to the truth to be satisfactory for template usage documentation, and "UTC" is much clearer to editors who see it mentioned on talk pages all the time. I mentioned noon to give a clue about why the template does the following:

• {{extract|juliandate|2451545}} → 1 January 2000
• {{extract|juliandate|2451545.25}} → 18:00 1 January 2000

Johnuniq (talk) 02:08, 11 October 2019 (UTC)