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Ron,
These errors you mention are why I gave my warning about cross checking the returned ephemerides against the position in your software.
If you enter an observatory code or Lat/Long & Altitude, the MPES will return topocentric ephemerides for your location.
Some software packages only calculate geocentric positions. During close approaches the difference becomes significant. From memory, Starry Night was out by more than 30 degrees for the passage of the NEO DA14. But that was an extreme case - DA14 passed between us and the Moon.
In this case, the 252P comet's range is about 20 million km so the geo/topocentric parallax should be less than 1 minute of arc. Clearly there is a problem with the orbital elements published, their input, or the software's orbital calculation. Joe
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