Meinolf, yes, the comments you made (about Mercury and Venus
conjunctions) did sort things out for me. In these cases, if you
start out with an inferior conjunction, Guide looks for successive
inferior conjunctions. Start out with a superior conjunction, and
Guide looks for those instead.

For example, for Mercury, conjunctions occur at roughly 58 day
intervals. Guide would skip every other conjunction, so it would
show them at 116-day invervals. I originally did things this way so
that transits would work in a logical way: I wanted Guide to find
cases where an inner planet winds up in front of the Sun, not the
more-common case where an inner planet goes behind the sun. (Click
on "Tables", "Miscellaneous Tables", "Elongations of Venus" (or
Mercury), and you'll see what I mean: in these tables, both types
of events are listed, and you can see that transits are rarer.)

Bernd, I can't say I knew of the M109/110 problem. However, I had
to fix up the Messier data recently, because with the new NGC-IC data,
you can 'go to' a slew of Messier objects and see a mismatch: Guide
centers on old coordinates, but the actual objects are shown with new
coordinates. (My thanks to Pat Madden for pointing this out.)

The fix is to download new Messier data (about 10 KBytes):

http://www.projectpluto.com/messier.zip

and unZIP it in your Guide directory.

-- Bill