[LEAPSECS] The relation between calendars and leap seconds.

Rob Seaman seaman at noao.edu
Thu Nov 13 22:42:01 EST 2008


M. Warner Losh wrote:


> Yes. But the times that I've proposed loosening DUT1 from +/- .9s (or

> is it +/- 1.0s? today) to something like 10s so that you could account

> for the long term trends of DUT1 and be able to predict out for 50

> years with reasonable degrees of certainty, the details get shot down

> by you, Mr. Seaman.


What special powers do I really have to shoot proposals down? Either
a proposal can stand on its own merits or it can't. In the former
case, why does my opinion matter any more than your own? If the
latter case, I guess you're saying that I pointed out actual flaws in
the logic. If you want to make a case for relaxing the balance
between DUT1 amplitude and scheduling horizon, go for it.


> In reality, an extreme form of this is the leap hour. It sets DUT1 to

> be ~3000x looser than it is today, and extends the mean solar time to

> be true on time scales measured in centuries rather than in terms of

> decades. There's really no difference between this and the other

> proposals, except the size of the corrections that folks interested in

> celestial positions will need to apply to their calculations.


The difference is that there is no coherent way to actually issue a
leap hour. These would not be the same thing as a DST adjustment. A
leap second happens at the same moment worldwide, so would a leap
hour. The only coherent way to do this is to make one really long
minute, otherwise you would be interpolating the 25th hour in between
different hours around the world.

Rob



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