[LEAPSECS] The Battle of Flodden Field

Rob Seaman seaman at noao.edu
Sat Jan 8 21:20:14 EST 2011

On Jan 8, 2011, at 3:54 AM, Tony Finch wrote:

> On 7 Jan 2011, at 20:53, Rob Seaman <seaman at noao.edu> wrote:


>> The proposal as written asserts that humans don't care about the synodic length of day.


> No, it says 86400 SI seconds is close enough for civil time. The aim is to reduce the need for synchronization adjustments - eliminate frequent fine adjustments and just use infrequent coarse adjustments instead. We care that the length matches the Earth well enough that the adjustments can do their job.

A proposal's "aims" should be explicitly stated. If "coarse" adjustments are planned, they should be discussed.

I do not believe the unstated magic timezone notion (if indeed that is an idea motivating the authors of the draft in front of the ITU) can work (or rather, I do not believe that this notion corresponds to a solution of the problem). The way to convince naysayers that a solution is actually being presented is to construct an engineering plan in detail.

It appears there are other unstated goals of the ITU actions, for instance, that TAI is to be deprecated. Note the irony of this situation. Precision timekeeping stakeholders want to redefine the mother-of-all atomic timescales. They choose to do this by redefining a different timescale to fill this roll under a different name. TAI itself isn't redefined - it is simply moth-balled to provide continuity of operations.

This is precisely what the Torino meeting advised should happen with UTC, should the mother-of-all civil timescales be supplanted - call the newly defined timescale something other than UTC.

The draft currently in front of the ITU is inadequate on its face. System engineering best practices are not controversial. They should be applied to this situation.


More information about the LEAPSECS mailing list