Importing the Washington Double Stars Catalog

[Jasem Mutlaq]

Yeah I already loaded the catalog from Vizer, always been a great service.
But it looks like there is a combined catalog already: Tycho Double Star
Catalogue (TDSC) (Fabricius+ 2002)

http://vizier.u-strasbg.fr/viz-bin/VizieR-3?-source=I/276/catalog

So we could use catalog instead of WDS directly. Another issues is that
Hipparcos data we're using appear to be J1991.25, so I also need to check
if we are assuming they're J2000 or someone performed the conversion before.

On Mon, Dec 5, 2016 at 12:46 PM, Christian Dersch <lupinix at mailbox.org>
wrote:

> Hi folks,
>
> I think we have to crossmatch WDS with Tycho-2 and/or USNO (which one
> btw?). Crossmatches can be done on identifiers (if both catalogs ship
> identifiers of one common catalog) or on position. A very easy to go
> solution is http://cdsxmatch.u-strasbg.fr/xmatch but using more powerful
> tools like Topcat or PyVO (be sure to use latest version) allows you to
> select columns from both catalogs, doing inner and outer joins using ADQL
> (astronomy relatex SQL dialect) and TAP services. For example we could
> create a Tycho-2 with just an WDS identifier in addition in that way. Or a
> WDS with Tycho-2 identifiers in addition. Or any other combination of both
> tables.
>
> Btw: Almost all catalogs (notable exception: Steinicke NGC) are availabe
> on VizieR: http://vizier.u-strasbg.fr/viz-bin/VizieR
>
> Greetings,
> Christian
>
>
>
> On 12/05/2016 09:56 AM, Jasem Mutlaq wrote:
>
> Hello folks,
>
> So I'd like to make the WDS as an addon catalog: http://www.usno.navy.
> mil/USNO/astrometry/optical-IR-prod/wds/WDS
>
> Note that I have problems accessing the website, I can only see the main
> page but any links within timeout.
>
> So what would be the best way to go on about this? The stars are "named",
> and a lot them are duplicates of either the static named/unnamed stars, or
> Tycho-2/USNO stars. So what are the recommended solution?
>
> 1. Import them as is "new stars" and ignore duplication. We need metadata
> for angular separation and position angle, and magnitudes of 1st and 2nd
> components.
> 2. "Extend" static/tycho/usno stars with the cross-reference information
> provided by WDS? We might miss some stars that are not found in either of
> those catalogs, highly unlikely, but possible.
>
> In either case, we need to extend the "metadata".
>
> On another note, I was checking  DeepStarComponent::loadStaticStars() and
> found that after each record read, it checks if it is 16 or 32 bytes. Can
> you mix 16/32 bytes within a single file?? If not, then no need to perform
> such a check after each record unnecessarily.
>
> --
> Best Regards,
> Jasem Mutlaq
>
>
>


-- 
Best Regards,
Jasem Mutlaq
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