cmo

I'm quite interested in having this feature and will happily look at implementing it myself if you'd be able to point me to where to start :)

Aha, good question, and something that should almost certainly be treated better in the docs. By default, and in the way most people use it, `VACUUM_TO_AIR` in `keyword.dat` is set...

If you would like to write up this example into a documented gallery example, I would be more than happy to accept a PR!

Indeed, the `Atmosphere` constructor can also take units too through the `.make_*d` statuc methods. Internally, everything is converted to SI, with the exception of wavelength in nm. This is discussed...