As I walk home along my road most nights in winter, I see the Moon and one-or-more planets.

Unsurprisingly, over the last 2 months, if it's been the same planet and it (and the Moon) has been in roughly the same place if I've arrived home at the same time.

If I stood in the same spot at the same time each day and took the same photo, I would be able to see Jupiter moving / appearing to move across the sky.

I think I've been told that we're now sufficiently good at Solar-System scale planetary mechanics that given a spot on earth and a date/time it's computationally trivial to recreate that night-sky.

Thus I conclude that that given any arbitrary Long-Lat, and particular time of day, and an arbitrary period ... it would be possible to draw a graph/chart of the locus of the planet (Jupiter, as it happens) over the course of that period.

... if you have the software and know how to use it 😅

Is there a site / program which will JustDoThis for me?

Is there a (free/cheap) program which will do this for me if I spend long enough learning how to configure the software to express what I want to see?

  • $\begingroup$ Apologies, I'm not au fait with the tags - feel free to add/remove appropriate tags $\endgroup$
    – Brondahl
    Jan 22 at 15:03
  • $\begingroup$ I'm pretty sure I've seen charts like this produced for, e.g. Venus, and that it was (IIRC) a cool a repeating pentagonal loop sort of thing. $\endgroup$
    – Brondahl
    Jan 22 at 15:04
  • 3
    $\begingroup$ 95% sure you can do this Stellarium, but I'd be lying if I said I knew how. Related: astronomy.stackexchange.com/questions/54104/… $\endgroup$
    – user267545
    Jan 22 at 18:19
  • 1
    $\begingroup$ I second @user267545: Stellarium is free and pretty easy to use. It can do exactly what you want, and if you're having trouble using it, there help to get on this site :) $\endgroup$
    – pela
    Jan 23 at 10:46
  • 1
    $\begingroup$ I also second @PM2Ring though: The Moon revolves around Earth in (a little less than) a month and hence moves ~10° per day wrt. the background stars. If you stretch your arm, the width of your fist shows you roughly how much it should move per night. $\endgroup$
    – pela
    Jan 23 at 10:46


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