Decoding Starlight SPECTRA

How spectra of stars can tell us a lot about stars - in particular the elements in stars. Relating atomic structure, and the transitions of electrons between different energy levels, to explain spectra - and how that identifies different elements in stars. Spectra can also indicate the type of star; O B A F G K M stars, whether a star is coming towards us, or noting further away, the temperature of the star and many more features. In 1925 Cecelia Payne-Gaposchkin described the abundance of elements in stars using the spectra of hundreds of stars but was persuaded that her results were wrong, with the most abundant by far being hydrogen and helium.
The origin of the atomic spectrum of hydrogen is described with the four lines in the emission spectrum, violet, blue, cyan and red. This includes the associated wavelengths of those colored bands in the emission spectrum.