Here we learn what the dark lines in the spectra of stars mean, and the history behind their understanding. Errata: Cecilia Payne-Gaposchkin - I made some mistakes about her in my video. Please note this page: OBAFGKM Classification: Wien's Law: Kirchhoff's three laws of spectroscopy: Edward Charles Pickering: Williamina Fleming: Annie Jump Cannon: Henry Draper Catalogue: Cecilia Payne-Gaposchkin; I made some mistakes about her in my video. Please note this page: Stellar Atmospheres; a Contribution to the Observational Study of High Temperature in the Reversing Layers of Stars.: Sloan Digital Sky Survey Sample Spectra, Data Release 5: T dwarf spectrum: Burgasser, et al, 2006: 0:00 Introduction 1:53 Colors of Stars 3:21 Wien's Law for Blackbodies 4:33 Spectra of Stars 5:50 Spectral Classification of Stars 7:30 The Harvard Classification System 8:29 Annie Jump Cannon 10:04 Cannon's Stellar Spectral Sequence 11:38 Henry Draper Catalog of Stars 12:47 Why are the absorption features all so different? 14:12 Cecilia Payne-Gaposhkin 16:19 Example: Hydrogen Lines 17:04 Two New Spectral Types: L and T 18:48 Modern Synthesis: The M-K System 20:29 Why is this Important? 22:19 Stellar Spectral Type Mnemonics 26:01 TDwarf stars: the "Brown Dwarfs" 26:30 Comparison of Type V Dwarf Star Spectra.