[Kstars-devel] KStars and custom catalog loading

[Mike McGavin]

Hi Jason.

On 08/07/06, Jason Harris <kstars at 30doradus.org> wrote:

> Thanks for your important feedback.  The biggest problem with custom
> catalogs is that it's a relatively untested feature.

> Can you send me your parsed Tycho-2 catalog fragment?  I'd like to try
> adding it as a custom catalog myself.

No problem -- I basically took tyc2.dat.00 (the fist of 19 main
sections of the catalog from a segment close to the North Celestial
Pole), pulled out the id, RA, Dec and vB, filtered out all stars
fainter than about mag 11.5, and re-formatted it into a 4 column
space-separated file.  Then I copied and adapted a header to match
another (much smaller) custom catalog that I'd generated
experimentally.

It still includes around 123,000 lines, and is about 600 kb after
gzipping, so I'll attach it to a separate email.

> One workaround that we can talk about is for you to add the Tycho
> catalog as a supplement to the current Hipparcos star catalog, rather
> than adding it as a separate custom catalog.  This will involve some
> very simple modification of the code, and some reformatting of the
> catalog (you'll also need to split your catalog files into files
> containing 1000 lines each; we do this for faster startup, as each file
> is read into a list of strings, and these strings are processed, rather
> than reading line-by-line while processing).  Let me know if you are
> interested in this option.

Thanks.  I'm certainly interested, but there's no urgency for me
personally, and I realise there are lots of other things you're
working on at the moment.  I've more been wondering what the state of
it is in general, and if it's something that might work more easily in
future versions or if there are any hacks I could try meanwhile.  If
it does end up being fixed in a 4.x release, I'd be quite happy to
wait (or experiment with KDE 4 just to see if I can get it working,
once I figure out how).

On the same topic, does kstars make any efforts to cross-reference
stars between different catalogs?  Tycho-2 comes with a field that
indicates the Hipparcos catalog number if a star's in both catalogs,
but I've tried to cross-reference catalogs manually before to get them
into a relational database (mostly for fun), and it was a nightmare
for all sorts of inconsistency reasons between the catalogs.


Thanks for the quick response.
Mike.