[BAA Comets] Astrometrica now downloads from MPC server

[Nick James]

Roger,

Thanks. That would probably explain why my reduction used fewer 
reference stars in the latest version.

The change is not as significant as the last update where my Rc mags 
changed by around 0.25:

http://lists.britastro.org/pipermail/comets-disc/2017-March/000920.html

People using Astrometrica for magnitudes should be aware of possible 
changes between releases and should always quote the version number when 
submitting data.

Nick.



On 03/04/2018 09:47, Roger Dymock wrote:
> Hi Peter, Nick,
> 
> The improved colour correction may refer to the restricted (B-V) range i.e.0.5<(B-V)<1.2 as described in the soon to be published paper by Richard Miles and myself. Such a restriction would reduce the number of reference stars. Using UCAC4 will return Rc rather than r mags, the approximate formula for which is Rc=r-0.22.
> 
> Astrometrica versions 420 and 424 returned r mags when using UCAC4. 431 returned Rc mags ditto and 433 introduced the (B-V) restriction mention above. Again this is explained in the aforementioned paper.
> 
> Regards
> Roger Dymock
> Skype; rogerdymock67
> Tel; 023 92647986
> 
> -----Original Message-----
> From: Comets-disc <comets-disc-bounces at lists.britastro.org> On Behalf Of Nick James
> Sent: 03 April 2018 07:09
> To: BAA Comets discussion list <comets-disc at lists.britastro.org>
> Subject: Re: [BAA Comets] Astrometrica now downloads from MPC server
> 
> Hi Peter,
> 
> Thanks for drawing attention to this and to Herbert for continuing to suupport this essential program.
> 
> Just one note. In Herbert's version history for the latest version
> (4.10.5.437) he says: "Improved colour correction for UCAC 4 and URAT 1". I'll try to find out exactly what this means since in the last change (to 4.10.0.431) there was a significant shift in UCAC-4 R magnitudes.
> 
> I've checked UCAC-4 R magnitudes reducing a couple of frames for
> 4.10.0.431 and 4.10.5.437 and they seem to be the substantially the same although the number of reference stars used changed from one version to the other.
> 
> Nick.
> 
> On 02/04/2018 20:31, Peter Carson wrote:
>> Hi All,
>> For those not aware Herbert Raab of Astrometrica has just released an update to Astrometrica that now downloads the MPCOrb data directly from the MPC https server. See www.astrometrica.at/download.html For several months Astrometrica was unable to download directly from this secure server which did make it a bit of a pain to keep the orbital elements data base up to date. See an extract from Herbert’s notes below note:
>> All the best
>> Peter Carson
> _______________________________________________
> Comets-disc mailing list
> Comets-disc at lists.britastro.org
> http://lists.britastro.org/mailman/listinfo/comets-disc
> 
> _______________________________________________
> Comets-disc mailing list
> Comets-disc at lists.britastro.org
> http://lists.britastro.org/mailman/listinfo/comets-disc
>