Hi Tiziano,

With the index markings: is it possible you don't have
the 'Round to nearest step' check-box set in the Add a Trail
dialog?

If the time in Guide is set to 2007 Jun 17 17:59:10,
and one generates a trail for an object with a one-day step
size and index frequency of 5, with the 'round to nearest
step' check-box turned on, then the first mark (for the 18th)
appears where the object would at 0:00 on June 18th. That
is, the time is rounded to an even multiple of one day.
(Similarly, if we had used a one-hour time step, the trail
would start at 18:00, and so on... Guide would round off
the step size.)

If the 'round to nearest step' check-box _isn't_ set, then
Guide assumes you want to start from exactly whatever time is
set in Guide. So you could get marks at 17:59:10 on June 18th,
19th, 20th, and so on. These would be labelled as 18, 19,
and 20, so you wouldn't necessarily realize that they weren't
for 0:00 on those days.

Regarding eclipse charts: yes, this is a problem of long
standing. It's not very noticeable on asteroid occultations,
more noticeable with solar eclipses, and _very_ noticeable
with extremely long events such as transits of Mercury and
Venus. I have some thoughts for fixing this; if I could, it
would also enable Guide to show some other interesting charts,
indicating times of disappearance/reappearance for lunar
occultations of stars. But thus far, I have only vague ideas
as to how to fix this (unless I rip out most of the code Guide
currently uses for drawing eclipses!)

-- Bill