Objects at high zoom wobble — but only when atmosphere is on

[10110111]

To reproduce, try the following steps:

1. Launch Stellarium
2. Make sure atmosphere is off
3. Go to Thebe (or, if your max zoom setting is too small, try Callisto)
4. Zoom in to see the ball, notice how clean and stable it is
5. Turn atmosphere on...

The screenshots of Thebe, as an extreme example:

• No atmosphere:

• Atmosphere on (this is just one screenshot of a continuously wobbling image):

I would suppose a problem with precision of projection, but given that without atmosphere everything is OK, the problem apparently is elsewhere.

[10110111]

I've found the problem: it's in the float-coarsening of the geometric angle of elevation in Refraction::innerRefractionForward that breaks things. I've tried removing all this coarsening from this method, so that calculations are all done in double, and now nothing wobbles.

[gzotti]

Thanks @10110111, that was the one case of float/double issue I mentioned I was intending to track down.

[github-actions]

Hello @10110111!

Thank you for suggesting this enhancement.

[github-actions]

Hello @10110111!

Please check the fresh version (development snapshot) of Stellarium:
https://github.com/Stellarium/stellarium-data/releases/tag/weekly-snapshot

[github-actions]

Hello @10110111!

Please check the latest stable version of Stellarium:
https://github.com/Stellarium/stellarium/releases/latest