306
in a field that, after the initial burst of activity by Secchi and his colleagues, had
largely developed elsewhere.
This chapter will follow the varying fortunes of astrophysics in Italy: from the
work of the pioneers; to the decline of spectroscopic studies at the turn of the nineteenth century; through their resurgence around the 1920s, especially thanks to the
exchange between George Ellery Hale (1868–1938) and Giorgio Abetti (1882–1982);
until the definitive affirmation of astrophysics in modern times.
18.2 The Italian Forerunners
The “founder of stellar spectroscopy” (at least according to Armellini 1939) was
Giovanni Battista Donati (1826–1873), assistant and, as of the end of 1859, director
of Florence Observatory. By 1856 Donati thought of using a prism to observe the
spectra of stars of different colors, in order to study their effects on scintillation and
stellar position but also to compare their dark lines with those observed in the Sun
(Galli et al. 2013). Using a single-prism spectroscope attached to a seventeenthcentury burning lens, Donati observed the spectra of 15 stars and made a preliminary classification, noting that “the stellar striae have a certain relation to the star’s
colours. Thus the white stars seem to have a family likeness; and so the yellow,
orange and red ones” (Donati 1863: 101).
Donati’s article, dated August 1860, lacks any discussion of the physical origin
of the “striae.” In fact, the astronomer could not have been aware of the concurrent
work by Kirchhoff on the identification of the sodium absorption lines in the solar
spectrum (Bianchi et al. 2016). When the paper was finally printed (in Italian,
French, and English, between 1862 and 1863), it encountered wide attention and
caused a rush of publications on stellar spectroscopy (Hearnshaw 2014). Among
them, there is the 1863 paper by Secchi, the first of the series that eventually led to
his classification of stellar spectra in five types (Chinnici 2019: 167–177; Altamore
et al., Chap. 1, in this volume). In turn, Secchi stimulated the interest of Lorenzo
Respighi (1824–1889), director of the Campidoglio Observatory in Rome, in spectroscopic studies. As Armellini (1939) stated, Respighi was the first to use an objective prism, a low-dispersion (small angle) prism in front of a telescope objective.
Together with photography, the use of the objective prism proved to be essential in
subsequent work on the classification of stellar spectra (for instance, the Henry
Draper Catalogue), since it allowed one to analyze several stellar spectra in the
telescope’s view field. The objective prism was also used by Secchi almost at the
same time as Respighi; a bitter dispute on the priority of this invention precluded
any collaboration between the two astronomers and, as a consequence, affected collaborations with other fellow spectroscopists (Chinnici and Gasperini 2013).
Besides stars, the early Italian spectroscopists also turned their attention to aurorae, zodiacal light, comets, planets, and, obviously, to the Sun. Donati and Secchi
had an interest in solar phenomena even before they made spectroscopic studies:
both observed the 1860 solar eclipse from Spain and concluded that the reddish
S. Bianchi
in a field that, after the initial burst of activity by Secchi and his colleagues, had
largely developed elsewhere.
This chapter will follow the varying fortunes of astrophysics in Italy: from the
work of the pioneers; to the decline of spectroscopic studies at the turn of the nineteenth century; through their resurgence around the 1920s, especially thanks to the
exchange between George Ellery Hale (1868–1938) and Giorgio Abetti (1882–1982);
until the definitive affirmation of astrophysics in modern times.
18.2 The Italian Forerunners
The “founder of stellar spectroscopy” (at least according to Armellini 1939) was
Giovanni Battista Donati (1826–1873), assistant and, as of the end of 1859, director
of Florence Observatory. By 1856 Donati thought of using a prism to observe the
spectra of stars of different colors, in order to study their effects on scintillation and
stellar position but also to compare their dark lines with those observed in the Sun
(Galli et al. 2013). Using a single-prism spectroscope attached to a seventeenthcentury burning lens, Donati observed the spectra of 15 stars and made a preliminary classification, noting that “the stellar striae have a certain relation to the star’s
colours. Thus the white stars seem to have a family likeness; and so the yellow,
orange and red ones” (Donati 1863: 101).
Donati’s article, dated August 1860, lacks any discussion of the physical origin
of the “striae.” In fact, the astronomer could not have been aware of the concurrent
work by Kirchhoff on the identification of the sodium absorption lines in the solar
spectrum (Bianchi et al. 2016). When the paper was finally printed (in Italian,
French, and English, between 1862 and 1863), it encountered wide attention and
caused a rush of publications on stellar spectroscopy (Hearnshaw 2014). Among
them, there is the 1863 paper by Secchi, the first of the series that eventually led to
his classification of stellar spectra in five types (Chinnici 2019: 167–177; Altamore
et al., Chap. 1, in this volume). In turn, Secchi stimulated the interest of Lorenzo
Respighi (1824–1889), director of the Campidoglio Observatory in Rome, in spectroscopic studies. As Armellini (1939) stated, Respighi was the first to use an objective prism, a low-dispersion (small angle) prism in front of a telescope objective.
Together with photography, the use of the objective prism proved to be essential in
subsequent work on the classification of stellar spectra (for instance, the Henry
Draper Catalogue), since it allowed one to analyze several stellar spectra in the
telescope’s view field. The objective prism was also used by Secchi almost at the
same time as Respighi; a bitter dispute on the priority of this invention precluded
any collaboration between the two astronomers and, as a consequence, affected collaborations with other fellow spectroscopists (Chinnici and Gasperini 2013).
Besides stars, the early Italian spectroscopists also turned their attention to aurorae, zodiacal light, comets, planets, and, obviously, to the Sun. Donati and Secchi
had an interest in solar phenomena even before they made spectroscopic studies:
both observed the 1860 solar eclipse from Spain and concluded that the reddish
S. Bianchi