Fun fact, When Newton was first working on his book Opticks in the 1670s to 1704, he had a lab with prisms, magnifying glasses, and telescopes. He never once used the telescope or magnifying glass to look at the spectrum produced by the prisms he was playing with.

But his work was published and available, which let others learn and grow the field.

Newton also sort of coined the word Spectrum, or at least stole it and put it to better use.