The orbits of Neptune's moons are not rendered correctly

[Carlo]

Stellarium Version 0.11.0 The red ellipse of the Laomedeia's orbit is irregular

Added by Bogdan Marinov:
The problem with moon orbits noticed by me in the comments applies for all planets with moons. See bug #889712:
https://bugs.launchpad.net/stellarium/+bug/889712
The issue with Laomedeia may be unrelated, as it looks visually different and appears even if the time is not changed.

[Bogdan Marinov (daggerstab)]

Wrong compared to what? Do you have light speed simulation turned on?

[Bogdan Marinov (daggerstab)]

We need to decide what to do about moon orbits. See bug #834727.
https://bugs.launchpad.net/stellarium/+bug/834727

[Shantanu Agarwal (shantanuag)]

Hi

The problem is not with the code, but with ssystem. The parameter names are case sensitive. Changing orbit_epoch and orbit_period to orbit_Epoch and orbit_Period under laomedeia solves the problem.

[Alexander Wolf (alexwolf)]

Oh, thanks! I think it's my fault.

[Alexander Wolf (alexwolf)]

O.K. I'm made a simple investigation of this issue and found troubles with rendering of orbits not related with typos for their elements.

Look at screenshots - it's like of troubles with rounding or double/float transformation.

[Alexander Wolf (alexwolf)]

Some time ago...

[Shantanu Agarwal (shantanuag)]

I'm sorry, I couldn't reproduce the error. Changing the time shifts the orbit appropriately. Could you please elaborate on how to reproduce the result you got. I used the qt-4.8-compact branch (recently created).

[Alexander Wolf (alexwolf)]

It's from trunk

[Shantanu Agarwal (shantanuag)]

I use windows and therefore can't compile from trunk with the latest revision. Could it be that this problem occurs only in trunk? That's highly unlikely though.

[Alexander Wolf (alexwolf)]

Revision 5305 enable Qt 4.8 compatible mode for trunk.

[Shantanu Agarwal (shantanuag)]

Thanks for that. But I couldn't reproduce the error even in this branch. When I change the time, the orbit also moves in sync with the planet.

[Guillaume Chereau (guillaume-chereau)]

I also cannot reproduce this bug. Need more information, or is this a Windows only issue?

[Guillaume Chereau (guillaume-chereau)]

OK, actually I confirm the bug (on linux 64bit). When I move the time, I eventually see something similar to the screenshot stellarium_000.png.

[Guillaume Chereau (guillaume-chereau)]

The problem seemed to be that the orbit positions of the satellites were computed while the parent planet sill holds its ecliptic position without light speed adjustment. We could make sure that the solar system bodies are always iterated in order from parent to children, or (as I just committed), call parent->computePositionWithoutOrbits first thing in Planet::computePosition.

Let me know if that induces any regression.

[Alexander Wolf (alexwolf)]

A fix has been committed as revision 7335 of the trunk branch of Stellarium's Bazaar repository at Launchpad: http://bazaar.launchpad.net/~stellarium/stellarium/trunk/revision/7335