87
Sirius with the hydrogen spectrum generated in a Geissler tube. He noticed a persistent shift in the starlight. On the assumption that this shift was due to a Doppler
effect, a radial velocity of this bright fixed star relative to the Earth of around
40 km/s resulted, corresponding to a wavelength shift of 1 Å.
For his contemporaries such velocities were so inconceivably high that, if that
was the implication, many were ready to dismiss Doppler’s theory, or at least its
validity for optical radiation. Huggins thus contradicted the common consensus of
an essentially static universe.
9
However, some of Huggins’s early measurements
9 It is to be remarked that, conversely, in Secchi’s opinion all the universe was in in motion (see
Tanzella-Nitti and Dolcetta, Chaps. 2 and 11, in this book).
Fig. 5.3 The first three of Secchi’s four classes of stellar spectra, chromolithographic plate by
Micheletti in Rome, from Secchi 1877: plate III. Online at http://starlight.inaf.it/1865/02/
limportanza- studi- non- isfugge- nessuno/ and http://starlight.inaf.it/artwork/arcetri- angelo- secchi- 1
818- 1878- 2/?lang=en. Also commented upon in the Giornale di Roma (1865), issue 2, p. 20
Fig. 5.4 A typical spectrum of class 4, from Secchi 1877; see https://malagabay.files.wordpress.
com/2017/10/secchi- class- iv.jpg and https://alchetron.com/Angelo- Secchi#demo
5 Angelo Secchi, Stellar Spectroscopy, Solar Physics, and Visual Science Culture
Sirius with the hydrogen spectrum generated in a Geissler tube. He noticed a persistent shift in the starlight. On the assumption that this shift was due to a Doppler
effect, a radial velocity of this bright fixed star relative to the Earth of around
40 km/s resulted, corresponding to a wavelength shift of 1 Å.
For his contemporaries such velocities were so inconceivably high that, if that
was the implication, many were ready to dismiss Doppler’s theory, or at least its
validity for optical radiation. Huggins thus contradicted the common consensus of
an essentially static universe.
9
However, some of Huggins’s early measurements
9 It is to be remarked that, conversely, in Secchi’s opinion all the universe was in in motion (see
Tanzella-Nitti and Dolcetta, Chaps. 2 and 11, in this book).
Fig. 5.3 The first three of Secchi’s four classes of stellar spectra, chromolithographic plate by
Micheletti in Rome, from Secchi 1877: plate III. Online at http://starlight.inaf.it/1865/02/
limportanza- studi- non- isfugge- nessuno/ and http://starlight.inaf.it/artwork/arcetri- angelo- secchi- 1
818- 1878- 2/?lang=en. Also commented upon in the Giornale di Roma (1865), issue 2, p. 20
Fig. 5.4 A typical spectrum of class 4, from Secchi 1877; see https://malagabay.files.wordpress.
com/2017/10/secchi- class- iv.jpg and https://alchetron.com/Angelo- Secchi#demo
5 Angelo Secchi, Stellar Spectroscopy, Solar Physics, and Visual Science Culture