S
WAstronomical spectroscopy
WBalmer jumpA
WDiffuse interstellar bands
WDoppler spectroscopyB
WH-alpha
WLong-slit spectroscopyC
WLyman-alpha blob
WLyman-alpha forestD
WDoubly ionized oxygen
WRedshiftE
WRossiter–McLaughlin effect
WSpectral imagingF
WSwan band
WWilson–Bappu effect