Hey everyone, Over the past few days I have been having trouble with finding research for my optics project. The topic I chose was supposed to be the physics behind how astronomer's and astrophysics measure the Spectrum of the Sun ans specifically the mathematics/physics behind the spectroscopy they use for our sun and others. According to my professor is called like "Ascell spectroscopy" with him pronouncing the "Ascell" like the phrase "a-shell". After 2-3 day of searching WebofScience, Galelio, Google Scholar, and even Wikipedia for this term, I come up with so little information that I think I have somehow completely butcher the spelling of "Ascell Spectroscopy" So if you guys could help me figure out the correct spelling of this word it would help out alot. Alternatively if you guys have the current name(s) of the specific spectroscopy(s) we use to measure the Sun that would help also.