Solar Spectrum

Solar Spectrum

 

Splitting white light into a spectrum using a prism is a familiar thing to many of use, but astronomers need a much finer instrument to create a spectrum they can use to study the Sun. Here, sunlight passed through a spectrometer at the McMath-Pierce Solar Facility at Kitt Peak, Arizona. The strength of light at each wavelength was recorded, then digitally reconstructed to form this image. The wavelength range is 700 nanometres (top left) to 400 nanometres (bottom right), with each of the 50 rows covering a range of just 6nm (one nanometre is a billionth of a metre). Dark lines show the absorption wavelengths of a variety of elements in the Sun’s atmosphere. Astronomers use such spectra to classify stars by their colour, age and composition. Our Sun, for example, is in spectral class G2V.

Image © Nigel Sharp, NOAO/NSO/Kitt Peak FTS/AURA/NSF

 

Light Works Logo small