Session 1, Page 10: Solar Spectrum

In 1814 Joseph von Fraunhofer, an optician, repeated Newton's prism experiment on sunlight with one major difference; he placed the prism that dispersed the light in front of a telescope, producing a highly magnified spectrum. As expected, a colorful spectrum was produced. However, to Fraunhofer's amazement he detected a series of dark, vertical lines superimposed on the bright spectrum as illustrated in Figure 14 below.

During the course of Fraunhofer's studies of sunlight he mapped over 600 of these dark absorption lines, referred to today as the Fraunhofer absorption lines. Currently we know of more than 30,000 of these absorption lines in the solar spectrum.

Fraunhofer did not have the opportunity to decode the messages in the dark spectral lines he observed. However, forty years later his research was taken up by a pair of chemists.

Figure 14
Example of solar spectrum showing the dark absorption lines observed by Fraunhofer. Image courtesy Mees Solar Observatory.

	Introduction to Solar Observing	Course Overview	Course Syllabus	Course Schedule
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