Stardates Explained - 19991210.0912

You don't understand the startdates?

Take, for example, 19991210.0912

Let me stick some spaces in some helpful places:

1999 12 10 . 09 12

That better?

19991210 means 10th December 1999, and 0912 is in 24-hour clock format, IE 9:12AM

Stardates in the Star Trek universe work in an entirely different way. Wikipedia has a good explanation on how Stardates work.