[time-nuts] Re: UTC - A Cautionary Tale

Rob Seaman seaman at noao.edu
Thu Jul 14 02:13:40 EDT 2005


> This is a little missive from an astronomer on the delicate subject  
> of the divergence of UTC from UTx. It seems that those bastards in  
> the precision timing community want to abandon UTC's leap seconds  
> entirely because they are too much trouble, and he's hopping mad.

Note that my message was composed for astronomers, not you guys.   
Several of us in the astronomical software community have been  
following this issue since before Y2K:


We are as "hopping mad" about the sneaky process as about the  
proposal.  Note our two tiered objection:  they not only propose to  
cease issuing leap seconds, they propose to continue calling the  
resulting time scale "Coordinated Universal Time".  There are many  
flavors of UT - UTC should not be divorced from the others.  Call a  
leap second-less civil time anything you want - simply don't call it  

> [His most amusing argument against modifying UTC is that astronomy  
> software tends to use UTC not UT1 etc.]

Amusing how?  Clocks must certainly represent the most familiar  
scientific instruments in households and offices worldwide.  People  
best use instruments that provide handy and simple measurements with  
minimal fuss.  All measurements are approximations of one type or  
another.  A one second level approximation of UTC - a measure of  
Earth Orientation - is extremely handy for folks who need such  
things.  Most people, most of the time, don't happen to need  
Universal Time to any great precision.  It is vital at other times.

Also note that UT1 is only available after the fact.  UTC is a  
deterministic (if segmented) timescale which provides not only an  
approximation (and prediction) of UT1, but also provides access to  
TAI two or three orders of magnitude more precisely yet.  It may not  
be perfect, but then - this proposal isn't designed to provide  
something better.  Imagine what might have been achieved if the  
precision timing community had spent the seven year leap second  
hiatus working to improve UTC rather than to sabotage it.

I find it surreal that it is the precision timing community who are  
arguing that the public have no need for access to precision time.

Rob Seaman

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