Alex clarified Stellarium's GRS use

Alexander responded to my Jupiter GRS Stellarium question(s).

He confirmed that rot_rotation_offset value has nothing to do with the "real" Jupiter GRS longitude. Stellarium uses it's own internal values for the longitude of planets.

He recommended determining a "good" value for offset manually, comparing against the visual appearance of the Jupiter. OK. That's how we're doing it now.

Alexander pointed out that since 0.11.4, the software has used a simple equation for calculating the shift of GRS. It is not ideal but better than before where the position was static.

Also, he confirmed my theory. The values are different between versions. It is related to texture file of Jupiter. And, the solar system initialisation file is updated on each release of the software.

And, finally, he also thought it very weird that Chris and I could not get the same results.

Quick!