[time-nuts] New leap second

[Tom Clark, K3IO]

   Chuck Harris commented

     Two leap seconds in as many years!
     It must be that global warming.
     -Chuck Harris

   UT1 is the time measured with respect to the stars, while UTC and TAI
   are based on the rate of  laboratory atomic clocks; I like to say that
   UT1 is the time you would read on your sundial.
   Since the earth's rotation is an imprecise clock, UTC is a hybrid that
   keeps your sundial's error to < 0.7 seconds (for the navigators, this
   means  <280 meters of east-west position error at the equator).
   In case anyone is interested, here is the actual UT1-UTC data produced
   by the group I headed for many years (until I retired in 2001):

     [cid:part1.06070202.03080904 at verizon.net]

   Here is what UT1-TAI (i.e. sundial - atomic clock) looks like without
   the steps. The ~30 second offset represent the accumulated error from a
   rather arbitrary historical date (1958, when the offset was set to 10.0
   seconds). The GPS clocks run on GPS time, which is nominally the same
   as TAI with a 19 second fixed offset (it was zeroed to UTC as of  Jan
   6, 1980, which is reckoned as the start of the GPS era).

     [cid:part2.02060709.08000401 at verizon.net]

   Regards, Tom
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 2008-07-04_16-45-44-274.png
Type: image/png
Size: 10534 bytes
Desc: not available
Url : http://www.febo.com/pipermail/time-nuts/attachments/20080704/87a08209/attachment.png 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 2008-07-04_16-52-09-860.png
Type: image/png
Size: 8788 bytes
Desc: not available
Url : http://www.febo.com/pipermail/time-nuts/attachments/20080704/87a08209/attachment-0001.png