wrote in message
ups.com...
I'm working on a project of modeling the stars of the constellations in
3-D; not for their positions relative to Earth, but relative to any
given person being at 0,0,0.

Search for the program "Celestia" on Google and download it. It's free. It
knows both the direction (RA and Dec) *and* distance (LY) of many stars and
allows you to position yourself anywhere in 3D space and see how things look
from there. If you go to the Navigation / StarBrowser menu item it brings up
a list of up to 500 stars giving, among other things, their distance in LY
from earth. Using these 3 polar coordinates (RA, Dec, LY) for any star you
can transform these polar coordinates into Cartesian coordinates (probably
using Z-axis is declination 90 degrees, X-axis is RA of zero hours, Y-axis
is RA of 6 hours). With these 3 computed X, Y, Z coordinates you would then
subtract a translation vector (delta-X, delta-Y, delta-Z) of a viewpoint
somewhere other than earth and you now have the X, Y, Z coordinates of your
chosen star *relative* to the new viewpoint.

Unfortunately, Celestia does not show you any of its own mathematics, but
this is essentially what it's doing.