Generally, the ultimate PypeIt spectrum output is a single spectrum per source, fully calibrated and (as desired) with a :doc:`telluric` performed.
The standard way to generate this file is with the :ref:`pypeit_coadd_1dspec` script.
The naming of this file is user-generated, i.e. it can be anything you wish.
The header of the primary extension includes the core_meta of PypeIt, e.g. RA, DEC, MJD, and configuration parameters of the instrument.
You view the spectrum using the lt_xspec script
(pypeit_show_1dspec will not work), which loads the data
and launches a GUI from the `linetools`_ package. e.g.:
lt_xspec J1217p3905_coadd.fitsInternally, the spectrum for a single object is held by the :class:`~pypeit.onespec.OneSpec` class.
Here is its datamodel, which is written as an `astropy.io.fits.BinTableHDU`_ in the first HDU of the file.
All wavelengths are in vacuum and flux units depend on whether :doc:`fluxing` was performed.