# 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:

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:

${\ displaystyle T = {\ frac {JD _ {\ text {Date}} - JD _ {\ text {Standard epoch}}} {36525}}}$

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 :

${\ displaystyle T = {\ frac {2415019 {,} 5-2433282 {,} 423} {36525}} = - 0 {,} 500012}$

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

${\ displaystyle T = {\ frac {2455197 {,} 5-2451545 {,} 0} {36525}} = 0 {,} 100000}$.

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

${\ displaystyle T = {\ frac {JD _ {\ text {Date}} - JD _ {\ text {Standard epoch}}} {365250}}}$.