It’s a beautiful spectrum. It reminds me to use the arc spectrometer I mentioned, obtain some pure iron (or as close as one could get in the iron grades) then obtain a spectrum. It’s an old spectrometer which I need to work out how to fix a camera to record the spectrum over the full wavelength range. I have somewhere, a spectrum of iron and all the major lines already printed in a fold out booklet of several A4 pages long (there are a lot of lines with relative intensities). I will get that copied. It would be nice to discover some exotic elements. But because of the binding energies of the atoms, there is a minimum which occurs around the atomic weight of iron, which I think? means iron is expected to be predominant in abundance (in the nuclear fusion processes of stars), next to cobalt and nickel in the periodic table. I will run cobalt and nickel. Might take me some time because I need a suitable connection to the spectrometer – if it still works?