spectroscope
A spectroscope is an optical device with which light is broken down into its spectrum and can be examined visually . If the light is directed to a receiver ( photo plate , CCD sensor, etc.), one speaks of a spectrometer .
A modern spectroscope has an entrance slit , an objective and a straight glass prism (or a corresponding grating ). A wavelength scale is usually also reflected in the field of view . The spectroscope was given its modern, almost straight-line form by Angelo Secchi SJ around 1870.
Spectroscopes are particularly versatile in astronomy . By observing the spectrum and determining the spectral class of fixed stars , galaxies or other celestial bodies, some of their properties can be determined, e.g. B. chemical composition, temperature , rotation or magnetic fields .
Spectroscopy was invented by the German optician Joseph von Fraunhofer , who discovered dark spectral lines in the solar spectrum in 1814/15 . Further milestones on the way to modern astrophysics were:
- 1858 the development of spectral analysis by Gustav Kirchhoff and Robert Bunsen
- In 1868 the stellar cosmology , when the first “dying” star γ CVn in the constellation Hunting Dogs was discovered by Angelo Secchi ( Vatican Observatory ) 400 light years away
- 1885 Johann Jakob Balmer's serial law for the spectral lines of hydrogen
- 1896 Pieter Zeemans discovery of the splitting of spectral lines when stars have a strong magnetic field ( Zeeman effect )
- In 1912 Vesto Slipher discovered the redshift in the light spectrum of distant galaxies
- 1913 the Hertzsprung-Russell diagram , which shows the relationship between the luminosity of a star and its spectral type
- 1925 determining the distance of the Andromeda by Edwin Hubble
See also
Web links
- Manfred Holl: Annie Jump Cannon (1863-1942) (astronomer, spectral classes, Secchi, Bunsen, star formation ...)
- Museum of Optical Instruments: Spectroscopes (some images)