More features for Observability Analysis

[alex-w]

Original report by Keatah: https://bugs.launchpad.net/stellarium/+bug/1045297

Observability Analysis plugin (ideas for more features)

Things to add to the plugin:

• [x] Distance from Sun for Solar System objects
• [x] Heliocentric x,y,z distances
• [x] More info for phases of the moon - Age, Angular Size.
• [ ] Some sort of graphical popup moon calendar
• [ ] Degree of subtention
• [x] Some sort of general astronomy calculator (this could be another plug-in or a totally different application entirely)

[gzotti]

Some of the numbers should be given only when accuracy issues have been solved. Else people would start using Stellarium as reference solution...

[axd1967]

Maybe overkill, but a dialog could be shown that warns the user about the accuracy of the graphs, or some other way to indicate that accuracy is not good for reference use? Just freewheeling: how about making the lines thicker, as fine lines imply high accuracy?

[gzotti]

@axd1967 Do you want to confirm a dialog for every numerical result that is technically wrong in the last displayed decimal figure? You will hurt your index finger from clicking.

Appendix F in the Stellarium User Guide is where you find accuracy estimates. As long as the version number is 0.*, you should not use Stellarium as reference source for numerical ephemerides.

[axd1967]

No... I was thinking about a one-time dialog with a checkbox that allows the user to hide it "forever" (or until reset by some other means). The dialog could contain one or more hyperlinks to one of these:

• https://github.com/Stellarium/stellarium/blob/master/guide/app_accuracy.tex,
• https://github.com/Stellarium/stellarium/blob/1dbadaec8e50a1cfdc681cfa99f8bc3dbf79414e/guide/app_accuracy.tex#L10-L30
• https://github.com/Stellarium/stellarium/releases/download/v0.19.2/stellarium_user_guide-0.19.2-1.pdf.

[gzotti]

I made such a one-time warning for users with too old computers that they should expect graphic problems. Those still reported about graphics problems. "Ah yes, there was some warning, but I clicked continue". Do you think anybody cares for what they confirmed when accepting some popup dialog that you see once just after installation or at first run?

[alex-w]

Couple features are implemented in main code already:

• [x] Distance from Sun for Solar System objects
• [x] More info for phases of the moon - Age, Angular Size.

Plus one feature is implemented in debug mode:

• [x] Heliocentric x,y,z distances

Probably we may add it in the release mode too, but... how it really necessary?

[alex-w]

What is "Degree of subtention" in astronomical application?

[alex-w]

I mark last item as solved due AstroCalc tool