Finder for sub-satellite point eclipse related events

[dmitrywalther]

No description provided.

[maisonobe]

The inertial frame should be extracted from SpacecraftState rather than hard-coded to EME2000.
Otherwise, the s.getPVCoordinates().getPosition() in the following line will be inconsistent.

[dmitrywalther]

I fixed it.

[maisonobe]

Hi, thanks for the PR.
Please note the github is only a mirror of our main forge. Pull requests should rather be registered on https://gitlab.orekit.org/orekit/orekit

[maisonobe]

Could also it be possible to add some unit test for the feature?

[wardev]

Interesting feature and good first cut at the implementation.

I think this makes the eclipse class too complex, it would be better as a separate class. Extracting an abstract super class would make sense since there is significant overlap in the code. Another option would be to use a Function that maps the SpacecraftState to the position considered for the eclipse calculation.

The withUmbraSSP and withPenumbraSSP methods do two things at once. Better for each method to do one thing. Use the existing withUmbra and withPenumbra instead of duplicating that functionality. Stylistically I prefer writing out acronyms so it is easier to read the code, e.g. withSubSatellitePoint(),