Stardates Explained - 19990804.1622

You don't understand the startdates?

Take, for example, 19990804.1622

Let me stick some spaces in some helpful places:

1999 08 04 . 16 22

That better?

19990804 means 4th August 1999, and 1622 is in 24-hour clock format, IE 4:22PM

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