Guy Harris said:
The notation of values of TAI using the Gregorian calendar is helpful when comparing time scales.
So how is that defined?
Do you just take a UTC value for the same instant, add the current TAI - UTC delta to it - and, for overflow (meaning "resulting seconds > 59 or minutes > 59 or...), "carry into" the calendar date, so that an event that took place at the end of 2018, with a UTC label, took place at the beginning of 2019, with a TAI label?
No. You take a Gregorian calendar (by default; in principle you could use Julian or something else) and use it to count *all* SI seconds, so that every day has exactly 86400 seconds in it. It works the same way as UT1, but without the unpredictable-length "seconds". You can convert that to UTC by subtracting the relevant (not "current") TAI-UTC delta and doing correct carries, remembering to handle the edge cases when the delta changes. -- Clive D.W. Feather | If you lie to the compiler, Email: clive@davros.org | it will get its revenge. Web: http://www.davros.org | - Henry Spencer Mobile: +44 7973 377646