A technique used by astronomers that allows them to determine the properties, such as composition, temperature, and motion through space, of celestial objects by analyzing the spectra of celestial objects. For example, because each atomic element absorbs and emits light in a unique set of wavelengths, the astronomer can sift through the spectrum of a star and determine what elements are present in the star's atmosphere. From the shapes and depths of spectral lines, the astronomer can calculate fundamental qualities of a star, such as how fast the gases churn through the stellar atmosphere or the star's effective temperature. An astronomer may also be interested in correlations between the abundances of certain elements and the physical behavior of the star, the age of the star, or the abundances of other elements. For instance, compared with the Sun, stars with low amounts of iron are also low in almost every other element with respect to hydrogen. Spectroscopy is performed by astronomers with instruments called spectrographs.

Radio Programs

Sheratan The hidden nature of a binary star Sunday, October 25, 2015
Cat’s Eye Nebula The true nature of a glowing cat’s eye Friday, August 29, 2014
Anders Angstrom Scanning the “barcode” of the Sun Wednesday, August 13, 2014
Companionship Looking for stellar companions Thursday, May 29, 2014
Annie Jump Cannon II Classifying the stars Wednesday, December 11, 2013
Castor Three sets of stellar twins Tuesday, January 15, 2013
More Capella Seeing a star in a different light Friday, December 7, 2012
Messengers The messengers of the stars Wednesday, February 2, 2011
Moon and Aldebaran Taking the measure of a bright star Monday, October 25, 2010
Rasalgethi A long trek for starlight Friday, May 7, 2010

Featured Images

Hobby-Eberly Telescope at McDonald Observatory
Searching the Darkness Friday, October 15, 2010


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