Merz Telescopes: A global heritage worth preserving (Historical & Cultural Astronomy)

This book comprises a fascinating collection of contributions on the Merz telescopes in Italy that collectively offer the first survey on historical large refracting telescopes in the country, drawing on original documents and photographs. It opens with a general introduction on the importance of Merz telescopes in the history of astronomy and analyses of the local and international contexts in which the telescopes were made. After examination of an example of the interaction between the maker and the astronomer in the construction and maintenance of these refractors, the history of the Merz telescopes at the main Italian observatories in the nineteenth century is described in detail. Expert testimony is also provided on how these telescopes were successfully used until the second half of the twentieth century for research purposes, thus proving their excellent optical qualities. Preface 6 Contents 8 Abbreviations 10 1 Big Is Beautiful: A Few Considerations About the Making of the Large 19th Century Refractors 11 1 The Prototype: Dorpat Refractor 12 2 Merz Refractors 13 3 Collaborators and Rivals 15 4 Glassmakers and Optical Glassmaking 19 5 Some Unsuccessful Cases 23 6 The Decline of Refractors 26 7 “Big Is Beautiful”: Yesterday and Today 27 References 28 2 The Merz Company: A Global Player of 19th Century 29 1 Joseph von Fraunhofer: A Sort of Hagiography 29 2 The Merz Company—Sources and Traces 31 2.1 Sources and Methods of Research 31 2.2 Trade Literature and Account Books 32 3 Epochs of the Optical Institute and Merz Company 34 3.1 The Founders of the Merz Company: Georg Merz and Joseph Mahler 35 3.2 The Period of Prosperity—Sigmund Merz: 1845–1883 35 3.3 The Last Active Members of the Merz Company—Jakob and Matthias Merz: 1883–1903 37 3.4 The Final Epoch—Merz-Zschokke: 1903–1932 38 3.5 Staff of the Merz Company—Invisible Hands 39 4 Data from Account Books and Other Sources 39 5 Merz as a Global Player—Different Types of Instrument 40 6 Why Did the Merz Company not Survive? 47 6.1 The Output of the Merz Company 47 References 48 3 The Maker and the Scientist: The Merz-Secchi Connection 49 1 Scientific Collaboration 51 2 Trading Aspects 54 3 Technical Questions 56 4 Not Only Telescopes: Spectroscopic Equipment by Merz 60 5 What Is Extant? 66 5.1 Star Spectroscope 66 5.2 Photograph of Secchi’s Solar Spectroscope 67 5.3 Objective Prism 72 5.4 Direct-Vision Spectroscope 75 5.5 Other Accessories 76 6 Final Remarks 76 References 77 4 The Padua Observatory and the Merz Workshop Under the Austro-Hungarian Empire 79 1 The First German Instruments at the Padua Observatory 79 2 Telescopes with Merz Optics Purchased Through the Polytechnic Institute of Vienna 83 3 Santini’s Journey to Germany 87 4 A New Telescope for the Observatory 88 5 An Important Addition: Dembowski’s Merz Telescope 91 References 95 5 The Merz Refractors at the Brera Astronomical Observatory 97 1 Schiaparelli and the Acquisition of Three Merz Telescopes 98 1.1 The First Merz Refractor at Brera 99 1.2 The Large Merz Refractor 101 1.3 A Third Merz Telescope 103 2 The Merz Telescopes After Schiaparelli 104 2.1 The Fate of the 22 cm Refractor 105 2.2 The End of the 49 cm Refractor 107 2.3 The Merz-Cavignato 110 Acknowledgements 110 References 110 6 Merz Telescopes in Rome 111 1 Introduction 111 2 The Merz Telescope at the Collegio Romano Observatory 112 3 The Merz Achromatic Telescope at the Campidoglio Observatory 116 4 Merz Telescopes at the Vatican Observatory 118 4.1 Merz Telescope I 119 4.2 Merz Telescope II 120 4.3 Merz Telescope III 121 5 Conclusions 122 References 123 7 On the Collection of Merz Instruments at the Naples Observatory 124 1 The Collection 124 2 The First Telescope Acquired by the Italian Government 125 3 The Long Life of the Neapolitan Merz Telescope 131 4 Other Instruments Related to Merz 134 4.1 The Annular Micrometer 134 4.2 The Prismatic Spectroscope 136 4.3 The Repsold Meridian Circle 137 4.4 The Ertel Theodolite 140 4.5 The Small Merz Telescope 141 References 143 8 A Merz Telescope on Mount Etna: The Catania Astrophysical Observatory 146 1 Introduction 146 1.1 The Astronomical Stations in the Etna Area 147 1.2 Bellini Observatory. A Merz Telescope on Mount Etna 148 1.3 The Merz Telescope at the Catania Observatory 155 2 Other Telescopes of the Late 19th and Early 20th Centuries 159 Acknowledgements 164 References 164 9 Double Star Measurement with the Merz Refractors at the Padova and Torino Observatories 165 1 Introduction 165 2 Telescope Resolving Power and Measurement Technique 167 3 The Padua Merz Refractor 169 4 The Turin Merz Refractor 171 5 Comparison and Evaluation of the Optical Quality of Objectives 173 5.1 Tests on the Dembowski Telescope 173 5.2 Tests on the Merz Telescope in Turin 175 References 176 Appendix A: A List of Extant Large Merz Telescopes (aperture = greaterthan 150 mm) Worldwide 178 Appendix B: List of Astronomical Instruments by Merz (1826–1932) 180 Index of Names 184 Index of Places 187 Index of Celestial Objects 190 Front Matter....Pages i-ix Big Is Beautiful: A Few Considerations About the Making of the Large 19th Century Refractors....Pages 1-18 The Merz Company: A Global Player of 19th Century....Pages 19-38 The Maker and the Scientist: The Merz-Secchi Connection....Pages 39-68 The Padua Observatory and the Merz Workshop Under the Austro-Hungarian Empire....Pages 69-86 The Merz Refractors at the Brera Astronomical Observatory....Pages 87-100 Merz Telescopes in Rome....Pages 101-113 On the Collection of Merz Instruments at the Naples Observatory....Pages 115-136 A Merz Telescope on Mount Etna: The Catania Astrophysical Observatory....Pages 137-155 Double Star Measurement with the Merz Refractors at the Padova and Torino Observatories....Pages 157-169 Back Matter....Pages 171-185