Helium was first detected as an unknown, yellow spectral line signature in sunlight, during a solar eclipse in 1868 by Georges Rayet, Captain C. T. Haig, Norman R. Pogson, and Lieutenant John Herschel, and was subsequently confirmed by French astronomer, Jules Janssen.
Source:
[1] “It’s Elemental – the Element Helium.” Jlab.org, 2021, education.jlab.org/itselemental/ele002.html#:~:text=Helium%2C%20the%20second%20most%20abundant,total%20solar%20eclipse%20in%201868.. Accessed 24 May 2021.
[2] Wikipedia Contributors. “Helium.” Wikipedia, Wikimedia Foundation, 14 May 2021, en.wikipedia.org/wiki/Helium. Accessed 24 May 2021.