In article
Is midnight 00:00 or 24:00?
Midnight is just midnight. The formatTime function will show it as "00:00".
I think that pretending to support UT1 and TAI on most computers is too much of a fiction to be justifiable in a library of this kind. The vast majority of programs don't need absolute time to sub-second accuracy, and the vast majority of operating systems can't even support UTC leap seconds correctly. Time specialists do need this stuff, but they'll have their own code.
TAI and leap-seconds are all in System.Time.TAI, so you don't have to worry about it. UT1 is necessary for historical time, since back-extending UTC is pointless and back-extending TAI completely hopeless. The UT1 type is really simple (ModJulianDate, a synonym for Rational that counts days), so there's not much extra complication. -- Ashley Yakeley, Seattle WA