<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Nov 20, 2015 at 1:12 PM, Steve Allen <span dir="ltr"><<a href="mailto:sla@ucolick.org" target="_blank">sla@ucolick.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">On Fri 2015-11-20T12:55:49 -0500, Marshall Eubanks hath writ:<br>
<span class="">> No, that will not work. The UTC clock is providing not just the time, but<br>
> also the rotation of the Earth (UT1). An atomic clock cannot do that (not<br>
> at the km level), and the tables cannot provide leap seconds (much) in<br>
> advance.<br>
<br>
</span>The almanacs are tabulated only a couple of years in advance, and over<br>
that short an interval the current predictions of earth orientation<br>
have errors about the same as the typical human error using a sextant.<br></blockquote><div><br></div><div><div>The USNO's MICA runs up to 2050, but of course does not include future UT1 variations. </div><div> </div></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
Full precision already needs the DUT1 = UT1 - UTC, so if the radio<br>
broadcast time signals and almanacs could arrange to agree on a new<br>
time scale then a new difference value would preserve that ability.<br>
<br></blockquote><div><div>Well, you could get WWV to announce UT1 - UTC offsets :)</div><div>But, then, you couldn't do celestial navigation off-shore with an FM or AM radio. </div></div><div><br></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
Full disclosure, Marshall and I worked across the building from each<br>
other using VLBI to measure earth orientation, so take this discussion<br>
as an example of why the ITU-R could not forge a working compromise.<br>
<div class=""><div class="h5"><br></div></div></blockquote><div><br></div><div>It does tend to give rise to discussion...</div><div><br></div><div>Marshall </div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div class=""><div class="h5">
--<br>
Steve Allen <<a href="mailto:sla@ucolick.org">sla@ucolick.org</a>> WGS-84 (GPS)<br>
UCO/Lick Observatory--ISB Natural Sciences II, Room 165 Lat +36.99855<br>
1156 High Street Voice: <a href="tel:%2B1%20831%20459%203046" value="+18314593046">+1 831 459 3046</a> Lng -122.06015<br>
Santa Cruz, CA 95064 <a href="http://www.ucolick.org/~sla/" rel="noreferrer" target="_blank">http://www.ucolick.org/~sla/</a> Hgt +250 m<br>
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