[fitsbits] Re: leap second alert

[Paul Schlyter]

In article <38582D3A.63CE at jach.hawaii.edu>,
Maren Purves  <m.purves at jach.hawaii.edu> wrote:
 
> Paul Schlyter wrote:
>> William Thompson <thompson at orpheus.nascom.nasa.gov> wrote:
>>>         (rest deleted)
>>> Personally, I would expect UT to mean either UTC or UT1.  This is one reason
>>> why letting UTC drift relative to UT1 is so troubling.
>> 
>> If one requires an accuracy large enough that the difference between
>> UT1 and UTC matters, then one should not just write "UT" (or "GMT"),
>> but instead explicitly specify if UTC or UT1 is used.
>> 
>>> The computer industry tends to use the acronym GMT as a synonym for UTC, but
>>> there's currently no exact recognized definition for GMT.
>> 
>> There have been several different definitions of GMT.  Earlier, GMT was
>> often considered equal to UT1.  Thus, the term "GMT" should be used only
>> when the difference between UTC and UT1 doesn't matter.
> 
> As long as they don't drift apart by too much, for both.
> If they are 20 minutes apart
 
Don't worry: by definition they can never be more than 0.9 seconds apart.
 
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