....Predictably, immediately after posting, I found the answer to my own
question. (The correct keywords appear to be the exact phrase "pioneer 10"
plus "ephemeris.")

I wound up at http://nssdc.gsfc.nasa.gov/space/helios/heli.html, and my
only remaining uncertainty is, is the origin of "Solar Ecliptic Coordinate
System" essentially equivalent to that of the standard astronomical R.A./DEC
coordinate system ??? And if so, can anyone verify my tentative deduction
that Pioneer 10 and 11's current apparent positions in the sky are in the
general celestial vicinity of the constellations Orion and Hercules,
respectively ???


-- Gordon D. Pusch

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