The limitation is not in just the STC reader.
The binary DB is also in float {32-bit}, as are all other handlers except the actual position information.
The position is held as an eigen 128-bit int, int128_t if you want a nice way of saying it.
Fixing this would require a rewrite and redesign of several steps.
The fix however, would break backwards compatibility with longtime DB.
It still needs to happens however.
I had a fork where I had rebuilt the DB with double instead of float{single} for positions, along with preserving RaDec.
It didn't add much time to loading, nor did keeping the Radec I added to the DB.
This was before I found other ways to generate to display realtime RaDec of selection focus items.
It was also nice since I could search via celx for stars via RaDecDist functions I added.
Sadly however, HDD failures do happen, and it was way back when the original forum was active.
I remember I had to modify the CPP DB builder because I could not figure out how to force perl to use double.
It shouldn't be very hard to switch to using doubles since eigen returns vector3d, which is three doubles in a record.
Code: Select all
Eigen::Vector3d pos =
astro::equatorialToCelestialCart((double) RA * 24.0 / 360.0,
(double) dec,
(double) distance);
x = (float) pos.x();
y = (float) pos.y();
z = (float) pos.z();
Or if there is a way to force perl to use doubles, this can be changed in buildstardb.pl as needed..
Code: Select all
foreach my $HIP (sort { $a <=> $b } keys %stars)
{
my $dist = PlxToDistance($stars{$HIP}{'Plx'});
my $theta = $stars{$HIP}{'RArad'} + pi;
my $phi = $stars{$HIP}{'DErad'} - pi / 2;
my @xyz = (
$dist * cos($theta) * sin($phi),
$dist * cos($phi),
-$dist * sin($theta) * sin($phi)
);
my $xc = $eqToCel[0][0] * $xyz[0] + $eqToCel[1][0] * $xyz[1] + $eqToCel[2][0] * $xyz[2];
my $yc = $eqToCel[0][1] * $xyz[0] + $eqToCel[1][1] * $xyz[1] + $eqToCel[2][1] * $xyz[2];
my $zc = $eqToCel[0][2] * $xyz[0] + $eqToCel[1][2] * $xyz[1] + $eqToCel[2][2] * $xyz[2];
my $absMag = AppMagToAbsMag($stars{$HIP}{'Vmag'}, $stars{$HIP}{'Plx'});
my $spType = ParseSpType($stars{$HIP}{'SpType'});
print DATFILE pack('LfffsS', $HIP, $xc, $yc, $zc, $absMag * 256, $spType);
print TXTFILE sprintf("%u %.9f %+.9f %.6f %.2f %s\n", $HIP,
rad2deg($stars{$HIP}{'RArad'}), rad2deg($stars{$HIP}{'DErad'}),
$dist, $stars{$HIP}{'Vmag'}, $stars{$HIP}{'SpType'});
}
Though I am not a real C/C++ programmer, so there may be some gotchas I don't know about.
Janus.
I don't know if this is possible, but I would suggest only adding extra precision to the STC file reader. The stars.dat file is fine right now, because high precision is only needed for stars that are very close together, like binary stars.