H-R Diagram Discipline: Education Having the information about spectral types was useful, but astronomers wanted to look for trends in the data. In 1911 Ejnar Hertzsprung plotted the absolute magnitude of stars against their colors. Two years later Henry Norris Russell independently did a similar graph using spectral types. Graphs of this type are known as Hertzsprung-Russell diagrams or H-R diagrams.Tags: starsluminositytemperatureHertzsprungRussellwhite dwarfblue giantsred giantssupergiants
Types of Stars Discipline: Education Astronomers have always been fascinated by the different sizes and colors of stars that they observed. In 1817 an German instrument maker named Joseph Fraunhofer attached a spectroscope to a telescope and pointed it at the stars. He found that different stars have different absorption lines in their spectra. At first astronomers did not understand why different stars would have different absoprtion lines. Nevertheless in the early 1900s, a team of astronomers at Harvard College Observatory started a project to examine the spectra of hundreds of thousands of stars.Tags: starsspectraspectral classtemperatureHenry DraperAnnie Jump CannonAntonia MauryEdward Pickering
