I am building a 3d model of the solar system and need to figure out the position of the pole stars of each planet in order to tilt the planets in the correct direction the correct amount. I've already found the information of the pole star locations, the problem is that these are in earth relative coordinates. For instance the pole star of Mars is Gamma Cygni at RA 20h 22m 13.70184s, Dec +40° 15' 24.0450".
Right Ascension (RA) is hours east from the prime meridian. Declination (Dec) is degrees north (+) or south (-) from the equator. These together define a position on an imaginary celestial sphere on the surface of which one can imagine all the stars.
So how do I go from those coordinates to a vector that defines the position of the star somewhere far far away on the celestial sphere?
I am using ThreeJS. This question points to a partial solution in terms of defining an origin for a sphere, or at least its texture.
I've posted the same question to Stack Overflow here in case some programmer wizard has the answer.