Parallaxes in file Nearstars.stc

[Joe]

Why the "Distance" values in the Nearstars.stc file is smaller than they should be. For instance, the Sun's Distance value in this file is 0.00326167. This value will make Celestia programme generate a 1Parsec = 206.265 AU which I think is wrong. It should in fact really be 3.26167 which makes 1 Parsec = 206265AU.

Is it a bug or not?

Joe

[ajtribick]

The distance value of the Sun in nearstars.stc has nothing to do with the value of 1 parsec.

As far as I know it is a "fudge factor" to make cel links created with old versions of Celestia (which stored parallax in the stars.dat file, which meant that the Sun could not be placed at the exact centre of the coordinate system) to work with the new version. So as to avoid breaking these links (which I feel is an inadequate reason, though others may disagree) the (unrealistic) offset is preserved.

[Brendan]

To fix it, I made the realsun.stc file in extras with the distance being 0.

Code: Select all

0 "Sol:Sun"
{
   RA 0
   Dec 0
   Distance 0
   SpectralType "G2V"
   AbsMag 4.83

   RotationPeriod      609.12  # 25.38 days
   Obliquity             7.25  # correct orientation relative to ecliptic
   EquatorAscendingNode 75.77  #
   RotationOffset       23.00  # standard meridian
}