7.6 Plan of Selected Areas
145
Fig. 7.15 Edward Charles Pickering (1846–1919), director of the Harvard College Observatory [75]
to actually use it in his private observatory where he managed to obtain the
spectrum of a star, namely the bright star Vega. This is α Lyrae, the brightest
star in the constellation Lyra and fourth brightest star in the sky. He noticed
that there were lines in the spectrum that were reminiscent of the spectrum of
the Sun. Hot, young stars for example have spectra that are dominated by lines
of helium and hydrogen, but in stars like the Sun these are less prominent and
the spectrum is dominated by atoms and ions (ions are atoms that have lost one
or more electrons) of other chemical elements such as sodium, calcium, iron,
and so on. The systematics of the stellar spectra has been extensively researched
under Edward Pickering, who thereby turned Harvard College Observatory
into a prominent observatory.
Draper recorded many more spectra of stars; after his death, his widow set
up a fund under the name of Henry Draper Memorial to make it possible to
further study this matter. This resulted in the Draper Catalog of Stellar Spectra,
published in 1890, with classifications of more than a thousand stars. This
classification was done in a newly conceived system and was mainly carried
145
Fig. 7.15 Edward Charles Pickering (1846–1919), director of the Harvard College Observatory [75]
to actually use it in his private observatory where he managed to obtain the
spectrum of a star, namely the bright star Vega. This is α Lyrae, the brightest
star in the constellation Lyra and fourth brightest star in the sky. He noticed
that there were lines in the spectrum that were reminiscent of the spectrum of
the Sun. Hot, young stars for example have spectra that are dominated by lines
of helium and hydrogen, but in stars like the Sun these are less prominent and
the spectrum is dominated by atoms and ions (ions are atoms that have lost one
or more electrons) of other chemical elements such as sodium, calcium, iron,
and so on. The systematics of the stellar spectra has been extensively researched
under Edward Pickering, who thereby turned Harvard College Observatory
into a prominent observatory.
Draper recorded many more spectra of stars; after his death, his widow set
up a fund under the name of Henry Draper Memorial to make it possible to
further study this matter. This resulted in the Draper Catalog of Stellar Spectra,
published in 1890, with classifications of more than a thousand stars. This
classification was done in a newly conceived system and was mainly carried