John Sauter wrote: >https://www.systemeyescomputerstore.com/proleptic_UTC.pdf.
Your abstract says you provide a leap schedule for 1900 to 1971, but actually you provide a leap schedule for -1000 to 1971. The abstract seems to suggest some distinction in objective between what is done for the 20th century and for the preceding 2900 years, aiming to "cover" the latter but "construct a table of leap seconds" for the former, a distinction that doesn't seem to make sense and doesn't actually exist in the paper. (You do give the leap table in a second format for the 20th century portion, but in substance this is only duplicating part of the table earlier in the paper.) Your proleptic leap schedule generally looks sane. I haven't checked the numbers in detail. It is good to incorporate Tony Finch's pUTC, as you do. Where more than 12 leaps are required in a year, your extension to leaping on the 15th day of a month is sensible. Your delta-T table confuses points in time with the intervals between them. The delta-T column itself applies to (the start of?) the specific year listed, but the "change in delta-T" and "seconds per year" columns apply to the interval between the year listed on that line and the year listed on the following line. The column labelling for that table, and its accompanying text, isn't great. You should state what delta-T means, address units, and generally make clearer what the table means. You write generally as if UTC exists only for 1972 onwards. You should acknowledge the existence of the former (1961 to 1971) rubber-seconds UTC, and make clear that your schedule is not a proleptic extension of the whole of UTC but only of the leap-seconds form of UTC. Your NTP material is mostly a mistake. For NTP's purpose of clock synchronisation, it needs to know about contemporary leap seconds, but has no need for knowledge of historical leap seconds. There is therefore no value, for this purpose, in extending the historical leap schedule further back. It is entirely erroneous to suppose that this paper has any bearing on NTP, and I see no value in the paper mentioning NTP. Some of the specific things you say about NTP are in error, but I won't go into detail due to this overriding concern. You should address the question, currently ignored, of what time scale your proleptic UTC is based on. If your aim is to fully construct a time scale, this is a necessary component. Actual UTC, both of the leap-seconds form and the rubber-seconds form, is defined as a transformation of TAI. TAI is only defined back to some time in 1955, because it is defined by the actual operation of atomic clocks. This covers Finch's pUTC, but you go far further back, millennia before there are any atomic clocks. The delta-T figures that you used are, strictly, referenced to TT. To construct a usable time scale you'll need to use something close to TT as the basis, and manage the transition between your proleptic basis time scale and the real TAI-based UTC. I'd be inclined to use the basis TAI(TT) = TT - 32.184 s prior to 1977, switching to TAI at 1977-01-01T00:00:00 TAI when by definition TAI(TT) = TAI, though this does mean using a different basis from the real UTC for five years of real leap-seconds-UTC history. It would be helpful for you to provide a distinctive name for the time scale that you construct. "Proleptic UTC" is a reasonable description, but not sufficiently specific to use as a name. -zefram _______________________________________________ LEAPSECS mailing list [email protected] https://pairlist6.pair.net/mailman/listinfo/leapsecs
