Collect line lists to use for wavelength calibration.

[crawfordsm]

See https://github.com/PYPIT/PYPIT/tree/master/pypit/data for possible starting point.

Collecting files from IRAF is another option.

[tepickering]

the first cut at this was done in #4. that included the IRAF line lists as well as some NIST lists from PYPIT. opened #27 to cover the need for a consistent file format.

[simontorres]

I know it is possible to do webscrapping of NIST site. I would direct your attention to NIST Strong Lines instead of atomic spectra database (this link) because the second contains too much lines that become noise at the end. At least for low/medium resolution spectroscopy.
Then the line list can be returned as a pandas.DataFrame.