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sci.geo.satellite-nav (Global Satellite Navigation) (sci.geo.satellite-nav) Discussion of global navigation satellite systems (GNSS). Topics include the technical aspects of GNSS operation, user experiences in the use of GNSS, information regarding GNSS products and discussion of GNSS policy (such as GPS selective availability).

IERS references

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Old May 12th 13, 12:57 PM posted to sci.geo.satellite-nav
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Default IERS references

"Universal Time is notionally based on the WGS84 meridian. Because of
changes in the Earth's rotation, the standard international time UTC
can differ from the mean observed time on the meridian by up to 0.9
second (equivalent to about 260 metres at Greenwich). Leap seconds are
inserted periodically to keep UTC close to Earth's angular position
relative to the Sun — mean solar time."


Is there one sane person who truly values their ability to reason and
adjust to better perspectives when necessary able to understand that
there was never such thing as the 'mean solar day',there is such a
thing as the mean of equal day that we know as the 24 hour AM/PM cycle
from which equable hours,minutes and seconds are extracted.

" Here take notice, that the Sun or the Earth passeth the 12. Signes,
or makes an entire revolution in the Ecliptick in 365 days, 5 hours 49
min. or there about, and that those days, reckon'd from noon to noon,
are of different lenghts; as is known to all that are vers'd in
Astronomy. Now between the longest and the shortest of those days, a
day may be taken of such a length, as 365 such days, 5. hours &c. (the
same numbers as before) make up, or are equall to that revolution: And
this is call'd the Equal or Mean day, according to which the Watches
are to be set; and therefore the Hour or Minute shew'd by the Watches,
though they be perfectly just and equal, must needs differ almost
continually from those that are shew'd by the Sun, or are reckon'd
according to its Motion." Christian Huygens


There is an obvious flaw in Huygen's reasoning which was corrected
later by John Harrison in creating the most accurate of watches for
determining East to West coordinates on the planet as the equal 24
hour cycle is derived directly from determination of the natural noon
cycle which is calculated within the 1461 cycle framework in a
365/365/365/366 day format.

As it each 24 hour cycle elapses it remains fixed to the natural noon
cycle and more importantly,the natural orbital cycle so that the
artificial equality instituted to allow one 24 hour day to follow the
next derives from equalizing the variations in the orbital component
hence the average 24 hour day also substituted for constant
rotation,of course,this is all occurs within the 365/366 day format.

The 'leap second' as a concept was always plain dumb and demonstrates
a lack of competence or confidence in timekeeping as a discipline and
especially where the references come from.Allowing for many phony
reputations built on a contrived framework such as idealized rotation
once in 24 hours back in the year 1820,there must be some genuine
people who can untangle a mess and resolve something which has existed
as a major thorn since the Galileo affair.The predictive convenience
of Ra/Dec must be partitioned from the Earth's planetary dynamics as
the former is based on the 365/366 cycle format covering 1461 cycles
to 4 orbital circuits to the nearest rotation while the latter is
based simply on a primal 365 1/4 rotations to 1 orbital circuit.


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