questions about UTC time, definitions, leap seconds, and measurement.



i've been looking into the NIST site on their standard expression of the
time:

http://tf.nist.gov/pubs/bulletin/leapsecond.htm

this brings me back several decades when i was a young ham radio operator
and i tuned into WWV to set my clock and to calibrate my 100 kHz frequency
calibrator.

i think i understand sufficiently what astronomical time is and what atomic
time is.

my first question was this:

by 1983, they must have expected about 1 leap second each mean year (1 part
per 31556952) why didn't they define the second to be that much longer (say
9,192,632,060 cycles instead of 9,192,631,770 cycles of this cesium
radiation? they would still have to add or subtract leap seconds
occasionally, but much less often than they did in the late 20th century.
why not, when you're *defining* the standard of time (with a much better
standard), make that initial definition agree as much as possible with the
known astronomical unit, and then stick to it?

my second question is:

what happened after 1999??? why are there no leap seconds after 1999 on
that web page? certainly it must have been updated since then? were there
*no* leap seconds added in the last 5 years?

just the curiosities of an anal-retentive engineer.

--

r b-j rbj@xxxxxxxxxxxxxxxxxxxx

"Imagination is more important than knowledge."


.

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