Historical & Cultural Astronomy Series Editor: WAYNE ORCHISTON, University of Southern Queensland, Australia ([email protected]) MARC ROTHENBERG, Smithsonian Institution (retired), USA ([email protected]) CLIFFORD CUNNINGHAM, University of Southern Queensland, Australia ([email protected]) Editorial Board: JAMES EVANS, University of Puget Sound, USA MILLER GOSS, National Radio Astronomy Observatory, USA DUANE HAMACHER, Monash University, Australia JAMES LEQUEUX, Observatoire de Paris, France SIMON MITTON, St. Edmund’s College Cambridge University, UK CLIVE RUGGLES, University of Leicester, UK VIRGINIA TRIMBLE, University of California Irvine, USA GUDRUN WOLFSCHMIDT, Institute for History of Science and Technology, Germany TRUDY BELL, Sky & Telescope, USA More information about this series at http://www.springer.com/series/15156 Ileana Chinnici • Guy Consolmagno Editors Angelo Secchi and Nineteenth Century Science The Multidisciplinary Contributions of a Pioneer and Innovator Editors Ileana Chinnici Guy Consolmagno INAF Vatican Observatory Osservatorio Astronomico di Palermo Vatican City State, Holy See Palermo, Italy ISSN 2509-310X ISSN 2509-3118 (electronic) Historical & Cultural Astronomy ISBN 978-3-030-58383-5 ISBN 978-3-030-58384-2 (eBook) https://doi.org/10.1007/978-3-030-58384-2 © Springer Nature Switzerland AG 2021 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifcally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microflms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specifc statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affliations. Cover image: Courtesy of the Rome Observatory, with modifcations by ilbusca/Getty Images/iStock This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland Preface Angelo Secchi is one of the most interesting fgures among the scientists of the nineteenth century. He is considered a pioneer of spectral classifcation of stars, a founder of modern astrophysics, and an innovator in spectroscopic techniques. Recent biographical studies have revealed many hidden aspects of his personality and research activities, showing his creative experimental approach, open-minded conceptual frame, and enthusiasm for the investigations. Though Secchi became well-known as an astronomer and astrophysicist, his background was in physics and he remained basically a physicist. He was interested to explore all natural phenomena, looking for their connections, and, consequently, extended his studies from astronomy and astrophysics to meteorology, geomagne- tism, geophysics, etc. His contributions in these felds are less known, but extremely interesting. They show how many innovations he introduced in these disciplines, inventing methods and devices that in some cases are still in use or were prototypes of modern machineries. Secchi was convinced that science should be at the service of the public (he con- tributed to develop and apply fre safety devices, earthquake prevention measures, water distribution systems, etc.) and involved the public in collecting data (a fore- runner of what is today called “citizen science”). At the same time, he was a brilliant communicator, disseminating scientifc knowledge in all social classes and raising interest and enthusiasm for the advancement of sciences and techniques. Ultimately, Secchi is a model not only for scientists, but also for everyone who cares about safeguarding and promoting the commonweal. For this reason, on the occasion of the bicentenary of his birth, a national com- mittee has been established and many initiatives has been organized to celebrate this anniversary: an international congress, an international workshop, a virtual exhibi- tion, a stage performance, and many public lectures and conferences. v vi Preface This book is a spin-off result of that effort and will undoubtedly show to the read- ers that pioneer and innovator are attributions rightfully applied to Secchi in many disciplines. Nichi D’Amico President of Istituto Nazionale di Astrofsica (INAF), Rome, Italy President of the National Committee for the Bicentenary of the Birth of Angelo Secchi Prof. D’Amico died unexpectedly in September 2020. We mourn his loss and dedi- cate this book in his memory. Angelo Secchi: Biographic Notes (Chinnici 2019) Figure: Drawing from a photographic portrait of Angelo Secchi (by Angelo Adamo; courtesy of INAF-OAPa) 1818 – Secchi is born at Reggio Emilia on June 28th into a middle-class family, the last son of Giacomo Antonio and Luigia Belgieri. 1833 – He enters the novitiate of the Society of Jesus in Rome; 4 years later, he studies philosophy at the Collegio Romano. His teachers of mathematics and physics are, respectively, Francesco De Vico and Giovan Battista Pianciani. 1841 – He teaches physics at the Jesuit Collegio Illirico at Loreto. 1844 – He returns to the Collegio Romano to study theology and becomes assistant to Pianciani. 1847 – He is ordained as priest. vii viii Angelo Secchi: Biographic Notes (Chinnici 2019) 1848 – After the voluntary exile of the Italian Jesuits, he is a refugee at Stonyhurst College, in England, then at Georgetown College, near Washington, D.C., in the USA. 1849 – Once back in Rome, he becomes Director of the Collegio Romano Observatory, following the untimely death of De Vico. 1852 – He moves the Observatory in a new site on the roof of St. Ignatius church, where he installs a new Merz telescope, 22 cm aperture; it becomes the main instrument of the Observatory, which is mainly devoted to astrophysics. 1862 – He is appointed Director of the Meteorological Service of the Papal State and starts a daily telegraphic correspondence among the stations for weather forecast. 1870 – He declines the offer of a chair of astrophysics at La Sapienza, from Italian government, as a consequence of the deteriorated relationship between Italian and Papal States. 1873 – He risks confscation of his Observatory due to a law that expropriates all properties belonging to the Catholic Church. 1876 – He keeps the directorship of Collegio Romano Observatory thanks to the Bonghi decree for the reform of the Italian Observatories, which assigns a spe- cial status to the Collegio Romano Observatory. 1877 – He is elected President of the National Board for Italian Meteorology. 1878 – Secchi dies in Rome on February 26th due to stomach cancer, which was diagnosed a few months earlier. Scientifc Activity Positional Astronomy His frst astronomical works were in the feld of astrometry: he revised the measure- ments of double stars included in the catalogue Mensurae Micrometricae by Friedrich Wilhelm Struve; this revision work was completed by Secchi’s assistant, G. S. Ferrari S. J. (Chinnici 2019: 63–65) Solar Physics This was his main research feld (Chinnici 2019:180–190; Ermolli and Ferrucci, Chap. 7, in this volume). He contributed to the study of solar radiation, photospheric features, spectroscopic analysis of chromospheres, and prominences, and wrote Le Soleil, one of the main nineteenth-century treatises about the Sun. In 1858, he installed a geomagnetic station at the Observatory in order to systematically observe Angelo Secchi: Biographic Notes (Chinnici 2019) ix geomagnetic perturbations and study their correlation with solar activity cycles; in 1863, he designed and built the thermoheliometer, a prototype of the bolometer. Stellar Spectroscopy Between 1863 and 1867, Secchi formulated one of the frst spectral classifcations of stars, dividing them into three classes (α-Lyrae type, α-Herculis type, sunlike type) and adding a fourth in 1869 (No. 152 Schjellerup type) and a ffth in 1872 (γ-Cassiopeiae type). He suggested the use of spectral analysis for measuring radial velocities in star proper motions via measurement of the Doppler shift of the spec- tral lines. In 1872, he extended his classifcation by using an objective prism (Lorenzo Respighi claimed priority in the use of this method). Secchi’s classifca- tion was the basis for all the later well-known classifcations carried out at the Harvard College Observatory (USA) at the end of the nineteenth century (Chinnici 2019: 167–177; Hearnshaw 1987: 57–66). Solar System Astronomy Thanks to the excellent optics of his Merz telescope, Secchi carried out detailed observations of planets, satellites, and comets. He paid special attention to planets Mars (McKim and Sheehan, Chap. 6, in this volume), Saturn, and Jupiter (trying to photograph them), and was the frst to observe the spectrum of Uranus,