Astronomical spectroscopy

The Spectroscopie is one of the principal means for the astrophysicists to study the Universe. In 1835, Auguste Count said in his Cours of positive philosophy that among the things which would remain forever out of reach human knowledge the chemical composition of the Sun appeared. He did not live long enough to see in 1865 two scientists German, Robert Bunsen and Gustav Kirchhoff to analyze for the first time the sunlight and to allow the determination of the Chemical composition of that Ci. Since this date, the astronomical spectroscopy did not cease progressing and the Spectrographe S make from now on integral part of all the astronomical observatories of the world.

The analysis of a spectrum brings a great quantity of information to us on the source which emitted the light, but also on the matter being between the source and us.

Various spectrographs

the spectrograph long-slit, which is identical to those that one uses in other sciences, and generally of weak and average spectral Résolution.
the spectrograph scale which makes it possible to optimize the use of the surface of the detector, and which makes it possible to reach very a spectral high-resolution.
the spectrograph with fiberoptic which uses a Fiberoptic in the place of a slit.
the spectrograph multi-objects which allows, thanks to masks multi-slits or with fibers to observe several objects at the same time.
the spectrograph with transform of Fourier.
the spectrograhe with integral unit of field.

Examples

UVES is a spectrograph scale in optics, installed with VLT.
FORS1 and FORS2 is two spectrographs optical, also installed with the VLT, and which makes it possible to as well make spectroscopy long-slit and multi-objects.
FLAMES is a spectrograph multi-objects, multifibre, with the VLT.

Internal bonds

Standard spectral

External bonds

spectra in short
History of the spectroscopy

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