On Jan 13, 2006, at 8:05 AM, Ed Davies wrote:
MJD 27123.5 means 12:00:00 on day 27123 if it's not a leap second day, but what does it mean on a day with a positive leap second? 12:00:00.5?
And we're back to the point in question. The precise issue is the definition of the concept of a "day". A leap second itself is a clearly defined moment in time.