[BAA Comets] Astrometrica now downloads from MPC server

[Roger Dymock]

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