in sense is given by the sign of the first
   degree term of the time-dependent polynomial for the body's prime
   meridian Euler angle &quot;W&quot;:  the spin is retrograde if this term is
   negative and prograde otherwise.  For the sun, planets, most
   natural satellites, and selected asteroids, the polynomial
   expression for W may be found in a SPICE PCK kernel.

   The earth, moon, and sun are exceptions: planetographic longitude
   is measured positive east for these bodies.

   If you wish to ove