"Seeing" is actually about how steady the atmosphere is. The old sodium lights emit in a narrow part of the spectrum which can be mitigated against by using lig

"Seeing" is actually about how steady the atmosphere is. The old sodium lights emit in a narrow part of the spectrum which can be mitigated against by using light pollution filters. These allow all light through, except sodium frequencies. Sadly, filters are ineffective against modern LED lighting which emits across a lot of the spectrum.