[Kstars-devel] branches/work/kdeedu_kstars_htm/kstars/kstars

[Jason Harris]

Hi James,

On Thursday 02 August 2007 16:36, James Bowlin wrote:
> SVN commit 695797 by jbowlin:
>
> I implemented re-indexing of the stars every 150 years.  I'm haven't
> run extensive tests yet to verify it is doing exactly what it is
> supposed to but it seems to be working and hasn't broken anything. The
> only big surprise was that it only takes 3 to 4 seconds to re-index
> all the stars on a single core of an amd64 3600+.
>
Excellent.  Can the re-indexing be performed in the background while the UI 
remains responsive?

> I'm working on precessing the constellation boundary polygons but this
> has turned out to be a little messy because the data is stored in
> QPointF's, not SkyPoints so I need to create a new SkyPoint for every
> point on the boundaries in order to do the precession.
>
Regarding the constellation boundaries: believe it or not, we actually should 
not precess them.  They were defined by the IAU in the 1930s to divide the 
sky into 88 regions, but the vertices of these lines are fixed RA/Dec values.  
They were actually drawn up using epoch 1875.0, so there are already 
significant offsets (for example, the southern border of Canis Minor is just 
below the equator, and is not quite parallel to it).

> I also need to re-index the constellation lines every 150 years just
> like I do for the stars because stars form the vertices of the
> constellation lines.  To do this the right way I will have to change
> the data members that hold the index in LineListIndex into pointers
> (instead of simply values).  I'll probably do this tomorrow.
>
It would probably make more sense to modify ConstellationLineComponent so that 
it stores a QList of pointers to the star objects themselves, rather than 
creating its own copies of these points.  I can try to take care of this if 
you agree it's a good idea.

regards,
Jason

-- 
KStars: KDE Desktop Planetarium
kstars at 30doradus.org