Hi Stefano

But you didn't say whether you have tried the UCAC3 stars to be _on_ and then used a small field setting only so that they don't flood the screen, to see if this makes any difference.

Also you didn't post the .idf details (I suppose your friend is using the .idf too).

Cut and paste the end of your ucac3.idf for hard disk, from around the

epoch 2000

part, or maybe the

pref part, and probably cut and paste the lines starting

mag

and

photo

these commands all have a bit of something to do with how things are plotted, and of course it's the old scientific method approach, if you suspect the .idf file, then rename it to .idb temporarily, or remove it, and use the English .tdf version to see if the same thing still happens. Then you'll know if it is a general problem or a ucac3.idf only problem.

Usually a typographic error in the photo line makes my copy of Guide crash (and once or twice crashing on launch), but I'm running an old version, some of the new versions could have fixed things such that it no longer crashes, but this may make it such that an old hidden bug is now seen, if there is a bug in Guide instead of in the .idf, whereas in the past Guide was too busy crashing to show any other problems.

For the photo line you can also put a ; at the front of the line to 'comment' it out, which will only make the difference of the stars being plotted as white instead of as colours matched to the 2MASS magnitudes. If the problem remains, the photo line is irrelevant. If it goes away, there's a problem in the photo line.

You say ucac3 from vizier works, you see, and there should be no difference in how the ucac3 from vizier and the ucac3 from hard disk .idf files work, no difference at all, because the plotting is using the same information. ucac3 has a new coordinates feature related to the proper motion that Bill included, if I remember rightly, and needs the volatile command. But if they work in one, they should work in the other, so some sort of typographic error would be my suspiscion. You could even try the Spanish tdf, but obviously you can read English so try the normal English .tdf instead of the .idf and see if the error repeats.

In all cases have Guide closed when making the editing or file changes and make sure you've made these changes in the Guide directory itself before restarting Guide.

John