After five years at Princeton, as part of an ongoing collaboration between Russell and research groups there, she moved to the Mount Wilson Observatory where she worked extensively on solar spectroscopy, analyzing the spectral lines of the Sun and thereby identifying the chemical elements in the Sun. With her collaborators, she analyzed the spectra of sunspots.[1] Moore was able to deduce the temperature of sunspots to be about 4,700 degrees kelvin.[8] Her pictures from the Mount Wilson Observatory helped redetermine the new International Angstrom scale.