I have used Guide 8 since it first came out and have rarely found any major discrepancies in the position of low numbered asteroids.

However I plotted 210, isabella, and tried to find it last night. No asteroid down to lm 17 with ccd. Eventually I got an ephemeris from the minor planet centre which placed it about a degree away. I printed a chart of this area from Guide and lo - there it was! As it is currently mag 13.9 it is a fairly easy target visually as well as for ccd work.

I am using MPCORB database, which I also downloaded and reloaded in Guide last night, so I am not sure as to what is causing the discrepancy. The dates are correct in Guide and the epoch is 2000. I checked Ceres, just to see if there were any discrepancies of position between the ephemeris and Guide, but that one was fine.

Any ideas? Am I missing an update that might cause this behaviour?

I am using XP as I could never overcome the display issues and crashes on my Windows 7 PC when zooming in further than level 7.

Many thanks for any help

Ian B