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<p class="MsoNormal"><span style="font-size:11.0pt">Hi all,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">I asked Maria Davis of the IERS Rapid Service / Prediction Center where to find EOPs. Her response is below. If you have any questions, feel free to reach out to her; she is not on the difx-user mailing list
but she is cc’ed and her email address is included below.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Best regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Sara Hardin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Earth Orientation Department, VLBI Division<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">U.S. Naval Observatory<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">3450 Massachusetts Ave. NW<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Washington DC 20392, USA<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">email: sara.e.hardin.civ@us.navy.mil<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black">Hi Sara,</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black"> </span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black">Thanks for forwarding. The official International standard for EOPs is the C04 (Paris Observatory: <a href="https://hpiers.obspm.fr/iers/eop/eopc04/eopc04.1962-now" title="https://usg01.safelinks.protection.office365.us/?url=https%3A%2F%2Fhpiers.obspm.fr%2Fiers%2Feop%2Feopc04%2Feopc04.1962-now&data=05%7C02%7Csara.e.hardin.civ%40us.navy.mil%7Cf831a33c4b78455bffc408ddc88ca267%7Ce3333e00c8774b87b6ad45e942de1750%7C0%7C0%7C63888"><span style="color:purple">https://hpiers.obspm.fr/iers/eop/eopc04/eopc04.1962-now</span></a>)
and Finals (USNO: <a href="https://maia.usno.navy.mil/ser7/finals2000A.daily.extended" title="https://usg01.safelinks.protection.office365.us/?url=https%3A%2F%2Fmaia.usno.navy.mil%2Fser7%2Ffinals2000A.daily.extended&data=05%7C02%7Csara.e.hardin.civ%40us.navy.mil%7Cf831a33c4b78455bffc408ddc88ca267%7Ce3333e00c8774b87b6ad45e942de1750%7C0%7C0%7C638887"><span style="color:purple">https://maia.usno.navy.mil/ser7/finals2000A.daily.extended</span></a>)
series produced by the IERS Earth Orientation Centre and IERS Rapid Service / Prediction Centre, respectively. </span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black"> </span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black">EOP data files, Bulletins A and B (and corresponding Finals and C04 series), can also be found on the IERS website (<a href="https://www.iers.org/IERS/EN/DataProducts/EarthOrientationData/eop.html" title="https://usg01.safelinks.protection.office365.us/?url=https%3A%2F%2Fwww.iers.org%2FIERS%2FEN%2FDataProducts%2FEarthOrientationData%2Feop.html&data=05%7C02%7Csara.e.hardin.civ%40us.navy.mil%7Cf831a33c4b78455bffc408ddc88ca267%7Ce3333e00c8774b87b6ad45e942de17"><span style="color:purple">https://www.iers.org/IERS/EN/DataProducts/EarthOrientationData/eop.html</span></a>).
CDDIS also hosts the Finals files (<a href="https://cddis.nasa.gov/archive/products/iers/finals2000A.daily.extended" title="https://usg01.safelinks.protection.office365.us/?url=https%3A%2F%2Fcddis.nasa.gov%2Farchive%2Fproducts%2Fiers%2Ffinals2000A.daily.extended&data=05%7C02%7Csara.e.hardin.civ%40us.navy.mil%7Cf831a33c4b78455bffc408ddc88ca267%7Ce3333e00c8774b87b6ad45e942de1750"><span style="color:purple">https://cddis.nasa.gov/archive/products/iers/finals2000A.daily.extended</span></a>).
However, IERS and CDDIS should be treated as backups to the original sources provided above.</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black"> </span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black">Depending on how the EOPs will be used, someone may also want a 3<sup>rd</sup> EOP series to compare values. In that case, I like to use the JPL SPACE solution (<a href="https://euler.jpl.nasa.gov/predictions/latest_midnight.eop" title="https://usg01.safelinks.protection.office365.us/?url=https%3A%2F%2Feuler.jpl.nasa.gov%2Fpredictions%2Flatest_midnight.eop&data=05%7C02%7Csara.e.hardin.civ%40us.navy.mil%7Cf831a33c4b78455bffc408ddc88ca267%7Ce3333e00c8774b87b6ad45e942de1750%7C0%7C0%7C638887"><span style="color:purple">https://euler.jpl.nasa.gov/predictions/latest_midnight.eop</span></a>).</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black"> </span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black">I’m not sure how the files linked below are generated/assembled, and therefore can’t speak to their validity. To support DiFX, I strongly recommend using an official IERS EOP series. Which series
to use depends on the specific use-case. Happy to discuss further if you have any specific scenarios.</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black"> </span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black">Kind regards,</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black">Maria</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black"> </span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black">Maria Davis (she/her)</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black">Lead Scientist, IERS Rapid Service / Prediction Center</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black">Earth Orientation Department</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black">U.S. Naval Observatory</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black">3450 Massachusetts Avenue NW<br>
Washington, DC 20392</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><i><span style="font-size:11.0pt;color:black"><a href="mailto:maria.a.davis33.civ@us.navy.mil"><span style="color:purple">maria.a.davis33.civ@us.navy.mil</span></a></span></i><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="font-size:12.0pt;color:black">From:
</span></b><span style="font-size:12.0pt;color:black">Difx-users <difx-users-bounces@listmgr.nrao.edu> on behalf of Adam Deller via Difx-users <difx-users@listmgr.nrao.edu><br>
<b>Date: </b>Sunday, July 20, 2025 at 10:30</span><span style="font-size:12.0pt;font-family:"Arial",sans-serif;color:black"> </span><span style="font-size:12.0pt;color:black">PM<br>
<b>To: </b>Leonid.Petrov@lpetrov.net <Leonid.Petrov@lpetrov.net><br>
<b>Cc: </b>Stuart Weston <stuart.weston@spaceops.nz>, difx-users@listmgr.nrao.edu <difx-users@listmgr.nrao.edu><br>
<b>Subject: </b>[Non-DoD Source] Re: [Difx-users] [Unrestricted] Getting EOP's {External}<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt">personally I use wget ftps://</span><a href="http://gdc.cddis.eosdis.nasa.gov/vlbi/gsfc/ancillary/solve_apriori/usno_finals.erp"><span style="font-size:12.0pt">gdc.cddis.eosdis.nasa.gov/vlbi/gsfc/ancillary/solve_apriori/usno_finals.erp</span></a><span style="font-size:12.0pt">.
gdc still exists, it just doesn't support ftp any more.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt">Cheers,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt">Adam<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt">On Mon, 21 Jul 2025 at 11:56, Leonid Petrov via Difx-users <</span><a href="mailto:difx-users@listmgr.nrao.edu"><span style="font-size:12.0pt">difx-users@listmgr.nrao.edu</span></a><span style="font-size:12.0pt">>
wrote:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt">Stuart,<br>
<br>
> How do people get the EOP's these days ?<br>
<br>
</span><a href="https://earthrotation.smce.nasa.gov/" target="_blank"><span style="font-size:12.0pt">https://earthrotation.smce.nasa.gov/</span></a><span style="font-size:12.0pt"><br>
<br>
Leonid<br>
<br>
> On 2025-07-20 21:39, Stuart Weston via Difx-users wrote:<br>
> We have a server that hasn't been used in anger for a while. It has<br>
> an install of DiFX on it which was "working".<br>
> <br>
> The "</span><a href="http://geteop.pl/" target="_blank"><span style="font-size:12.0pt">geteop.pl</span></a><span style="font-size:12.0pt">" doesn't appear to work any more. It is trying to use<br>
> :<br>
> <br>
> </span><a href="ftp://gdc.cddis.eosdis.nasa.gov/" target="_blank"><span style="font-size:12.0pt">ftp://gdc.cddis.eosdis.nasa.gov</span></a><span style="font-size:12.0pt"><br>
> <br>
> I don't get a response from it.<br>
> <br>
> I have found EOP's here : </span><a href="https://eop2-external.jpl.nasa.gov/" target="_blank"><span style="font-size:12.0pt">https://eop2-external.jpl.nasa.gov/</span></a><span style="font-size:12.0pt"><br>
> <br>
> But not sure how to map the columns to what DiFX requires.<br>
> <br>
> How do people get the EOP's these days ?<br>
> <br>
> Dr Stuart Weston<br>
> <br>
> PhD, MPhil(Hons.), BSc(Hons.)<br>
> Warkworth Station Manager<br>
> 121 Satellite Station Road, Warkworth 0983<br>
> <br>
> Space Operations New Zealand Ltd<br>
> PHONE +64 21 713 062<br>
> ADDRESS Hargest House, 62 Deveron Street, PO Box 1306, Invercargill<br>
> 9840, New Zealand<br>
> <br>
> </span><a href="http://www.spaceops.nz/" target="_blank"><span style="font-size:12.0pt">www.spaceops.nz</span></a><span style="font-size:12.0pt"> [1]<br>
> <br>
> <br>
> <br>
> Links:<br>
> ------<br>
> [1] </span><a href="https://spaceops.nz/" target="_blank"><span style="font-size:12.0pt">https://spaceops.nz/</span></a><span style="font-size:12.0pt"><br>
> _______________________________________________<br>
> Difx-users mailing list<br>
> </span><a href="mailto:Difx-users@listmgr.nrao.edu" target="_blank"><span style="font-size:12.0pt">Difx-users@listmgr.nrao.edu</span></a><span style="font-size:12.0pt"><br>
> </span><a href="https://listmgr.nrao.edu/mailman/listinfo/difx-users" target="_blank"><span style="font-size:12.0pt">https://listmgr.nrao.edu/mailman/listinfo/difx-users</span></a><span style="font-size:12.0pt"><br>
<br>
_______________________________________________<br>
Difx-users mailing list<br>
</span><a href="mailto:Difx-users@listmgr.nrao.edu" target="_blank"><span style="font-size:12.0pt">Difx-users@listmgr.nrao.edu</span></a><span style="font-size:12.0pt"><br>
</span><a href="https://listmgr.nrao.edu/mailman/listinfo/difx-users" target="_blank"><span style="font-size:12.0pt">https://listmgr.nrao.edu/mailman/listinfo/difx-users</span></a><span style="font-size:12.0pt"><o:p></o:p></span></p>
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<o:p></o:p></span></p>
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<span class="gmailsignatureprefix">-- </span><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.5pt">!=============================================================!<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.5pt">Prof. Adam Deller <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.5pt">Centre for Astrophysics & Supercomputing <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.5pt">Swinburne University of Technology <br>
John St, Hawthorn VIC 3122 Australia<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.5pt">phone: +61 3 9214 5307<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.5pt">fax: +61 3 9214 8797<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.5pt">!=============================================================!<o:p></o:p></span></p>
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