Their guesswork has now been replaced by a more accurate model.

Eventually, perfectly concentric spheres were abandoned as it was impossible to develop a sufficiently accurate model under that ideal.

An accurate model will closely match the verification data even though these data were not used to set the model's parameters.

However, a more accurate model takes into account relativistic and spin effects, which break the degeneracy of the energy levels and split the spectral lines.

However, the accurate model performed properly in the simulated atmosphere.