Hi Martin,

At present, Guide has no feature of this ilk. It would probably
be most useful in cases such as showing where Mercury is at twilight:
you would see its position, night after night, at the time when the
sun was at a specified distance below the horizon. The position of
Mercury on the chart would indicate the difference in azimuth relative
to the Sun (that is, Mercury would drift "left" or "right" depending
on where it was above the sun, _not_ some fixed point on the horizon).
It would all get very messy very quickly... and if anything but the
Sun and Mercury were in the display, it would get messier still.

But it might be useful for showing where Mercury, Venus, or
comets were each evening or morning. For conjunctions, it would
probably be less useful; there, it will often make more sense
just to generate trails for both objects.

I'm not very optimistic about being able to add this feature.
It _does_ sound as if somebody has probably attempted to create such
charts, though; can anyone recommend a program that does this?

-- Bill

------- Original message: ---------
Hello,

I would like to create a trail to demonstrate, how a planet moves in
relation to an other planet or the sun.

This could be used to generate visibility diagrams of mercury during
twilight or to explain the relative motion of sund and moon during
conjunction.

This would require fixing one object in the field of view and creating
trails for one or many others. Non mooving objects should probaly be
invisible for this kind of display.

Is that possible today? Could it be added?

Regards, Martin