# Julian century

A **Julian century** is defined as the duration of 36,525 days, i.e. 100 Julian years of 365.25 days each.

The *day* was understood to mean:

- earlier a mean sunny day
- since 1960 one day to 86,400 ephemeris seconds
- Today is a day of 86,400 seconds of the International System of Units .

Ten Julian centuries make up a **Julian millennium** .

## application

In astronomical calculations, the number of Julian centuries since a standard epoch is often required for a specific date . Usually the symbol *T is* used for this . The value results as:

JD stands for the respective Julian date . For a date earlier than the standard epoch, T is negative.

Examples: Julian centuries on December 31, 1899 00:00 Universal time since B1950.0 :

Julian centuries on January 1, 2010 00:00 DD since J2000.0 :

- .

Accordingly, the number of Julian millennia since a standard epoch results as:

- .