What is the best database for identification of spectral lines? What is the best database for the identification of spectral lines? For instance, I have a red spectrum of A0 star and I would like to recognize the most prominent lines, where to find them? Many thanks.
EDIT:
Why is O2 line not in NIST? It would be about 2676.99 A.

source: http://www.spektros.de/sirius/sirius.html
After advice:
How to install the database for molecules https://bitbucket.org/OES_muni/massiveoes/src/master/? I obtained the following error:
python setup.py develop
/home/linux/.local/lib/python2.7/site-packages/setuptools/dist.py:474: UserWarning: Normalizing '1.001' to '1.1'
  normalized_version,
running develop
error: can't create or remove files in install directory

The following error occurred while trying to add or remove files in the
installation directory:

    [Errno 13] Permission denied: '/usr/local/lib/python2.7/dist-packages/test-easy-install-547.write-test'

The installation directory you specified (via --install-dir, --prefix, or
the distutils default setting) was:

    /usr/local/lib/python2.7/dist-packages/

Perhaps your account does not have write access to this directory?  If the
installation directory is a system-owned directory, you may need to sign in
as the administrator or &quot;root&quot; account.  If you do not have administrative
access to this machine, you may wish to choose a different installation
directory, preferably one that is listed in your PYTHONPATH environment
variable.

For information on other options, you may wish to consult the
documentation at:

  https://setuptools.readthedocs.io/en/latest/easy_install.html

Please make the appropriate changes for your system and try again.
There is the NIST Atomic Spectra Database where you could browse by elements. This the reverse approach, meaning that you have to first query element by element and then see which of the lines you find in the spectrum - that's how we used to do it in our labs during studies:

Then, there is another NIST site where you can enter up to 4 spectral lines in units of electron Volt to be identified:

I am aware that there is also at least one old commercial software (some name starting with Win) to do that, running under Windows 3.1.
There is also custom written C-code used by research groups working on the topic, but I have to dig to figure out whether these software is still available. All I found is a software called Spectrum Analyzer which I have not tested.