# How do I calculate the cartesian coordinates of stars

Given the Right ascension in h m s, Declination in deg ' " and the Trigonometric parallax How can I get the cartesian (x,y,z) coordinates of a star? I'm guessing I need 3 separate formulas to get each x, y and z values.

-
Why do you need Cartesian coordinates? In any event... –  Ｊ. Ｍ. Dec 23 '10 at 10:09
Then your declination corresponds to $\theta$, right ascension to $\phi$ and parallax to $r$ for a properly referenced spherical coordinate system. See en.wikipedia.org/wiki/Spherical_coordinate_system –  Ross Millikan Dec 23 '10 at 14:15
@J.M. to plot thing in openGL you need Cartesian coordinates. @Ross - Thanks I'll look into it. –  Justin808 Dec 24 '10 at 20:16