Stellarium

This is probably related to bug #834737, or at least to my observation in the comments of the bug report:
https://bugs.launchpad.net/stellarium/+bug/834737
The original issue with Laomedeia may be caused by using an osculating orbit instead of proper elements.

Anyway, to reproduce this bug:
1. Turn on orbits.
2. Zoom in on a planet that has moon orbits enabled _without selecting the planet_ (because that will show only its orbit).
3. Either change the date/time or increase time speed.

I think that the bug will be evident even without changing the time - if Stellarium runs long enough for the satellites or the parent planet to significantly change position. Someone should let Stellarium run for a few hours with orbits enabled. :)

I think that this is a problem with Stellarium's orbit rendering code. It was simply not made with planetary satellites in mind. Enabling orbits for every possible satellite was a hasty move.

Changed in stellarium:
status:	New → Confirmed

Revision history for this message

Bogdan Marinov (daggerstab) wrote on 2011-11-13:

Jupiter inner satellites - broken orbits in normal drift.png Edit (58.0 KiB, image/png)

I tried leaving Stellarium run for a few minutes with the orbit lines toggled on. This was enough for the orbits of the innermost satellites to show the distortion (see the attached screenshot).

summary:

- Planet's moon orbits line display wrongly when I chang the time
+ Moons' orbit lines broken by parent planet movement with time

Revision history for this message

Shantanu Agarwal (shantanuag) wrote on 2012-04-01:

orbit.patch Edit (3.0 KiB, text/plain)

I've tried to fix the problem (patch attached) by updating the orbits to keep up with the parent planet. Simply recalculating the orbit using VSOP87 each second would have been too costly, so I kept a record of previous orbit points in it's parent planet's frame and transformed them to keep the orbit up with the parent planet's movement. It seems to be working fine, but updating all the orbits is still costly and wasteful, as all of them will not be rendered at the same time. I think it is possible to update only those orbits that will be rendered. Please comment.

Revision history for this message

Alexander Wolf (alexwolf) wrote on 2012-04-01:

Your patch are solved this problem with low cost and it good for me.

Changed in stellarium:
assignee:	nobody → Shantanu Agarwal (shantanuag)
milestone:	none → 0.11.3
status:	Confirmed → Fix Committed

Revision history for this message

Alexander Wolf (alexwolf) wrote on 2012-04-01:

A fix has been committed as revision 5276 of the trunk branch in Stellarium's Bazaar repository at Launchpad:
http://bazaar.launchpad.net/~stellarium/stellarium/trunk/revision/5276