Baars / Kärcher Radio Telescope Reflectors

Historical Development of Design and Construction
1. Auflage 2017
ISBN: 978-3-319-65148-4
Verlag: Springer International Publishing
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, Band 447, 282 Seiten

Reihe: Astrophysics and Space Science Library

This book demonstrates how progress in radio astronomy is intimately linked to the development of reflector antennas of increasing size and precision. The authors describe the design and construction of major radio telescopes as those in Dwingeloo, Jodrell Bank, Parkes, Effelsberg and Green Bank since 1950 up to the present as well as millimeter wavelength telescopes as the 30m MRT of IRAM in Spain, the 50m LMT in Mexico and the ALMA submillimeter instrument. The advances in methods of structural design and coping with environmental influences (wind, temperature, gravity) as well as application of new materials are explained in a non-mathematical, descriptive and graphical way along with the story of the telescopes. Emphasis is placed on the interplay between astronomical and electromagnetic requirements and structural, mechanical and control solutions. A chapter on management aspects of large telescope projects closes the book. The authors address a readership with interest in the progress of engineering solutions applied to the development of radio telescope reflectors and ground station antennas for satellite communication and space research. The book will also be of interest to historians of science and engineering with an inclination to astronomy.

Jacob W. M. Baars obtained the Ir- and Dr. Ir.-degrees in physics from the Technical University Delft in 1963 and 1970, respectively. After a three year stint at the National Radio Astronomy Observatory (USA) he joined the Netherlands Foundation for Radio Astronomy in 1966. There he participated in the construction and commissioning of the Westerbork Synthesis Radio Telescope and directed its operation from 1972. Upon moving to the Max-Planck-Institut für Radioastronomie in Bonn in 1975, he was project manager of two advanced millimeter wave radio telescope projects - the IRAM mm-telescope on Pico Veleta, Spain and the Heinrich Hertz Telescope on Mt. Graham, Arizona, USA. He served as Project Scientist during the definition and design phase of the Large Millimeter Telescope of Mexico/University of Massachusetts. In 1999 he joined the ALMA group at the European Southern Observatory in Garching, where he performed tasks in management, system engineering and in particular the design, construction and evaluation of two prototype submillimeter radio telescopes. Since his retirement he has acted as consultant to radio telescope projects and participated in project review committees, in particular the Square Kilometre Array.Hans Jürgen Kärcher obtained the Dipl.Ing. and Dr.-Ing. degrees in structural and mechanical engineering from the Technical University in Darmstadt in 1968 and 1974, respectively. He joined MAN Gustavsburg, (now MT Mechatronics) in 1974, initially as system engineer for telescopes and communication antennas. From 1986 up to retirement in 2006 he was head of research and development programs. From 2006 to now he is consultant for telescope mechanics, associated with MT Mechatronics, Mainz. He was project manager and/or lead system engineer for about 40 major telescope projects, optical as well as radio. Highlights were e.g. the 30m Millimeter Radio Telescope MRT IRAM in Spain, the 50m Large Millimeter Telescope LMT/GTM in Mexico, the 2.7m Stratospheric Observatory for Infrared Astronomy SOFIA in the US, and the 4m Advanced Solar Telescope ATST/DKIST on Maui, Hawaii.

Autoren/Hrsg.

Baars, Jacob W. M.

Kärcher, Hans J

Inhaltsverzeichnis

1;Preface;7
2;Contents;10
3;Chapter 1: Introduction;14
4;Chapter 2: Evolution of the Telescope;21
4.1;2.1 Some History;22
4.1.1;2.1.1 Early Optical Telescope Efforts;22
4.1.2;2.1.2 Emergence of Electromagnetic (Radio) Waves;25
4.2;2.2 General Characteristics of Optical and Radio Telescopes;27
4.2.1;2.2.1 Introduction;27
4.2.2;2.2.2 Types of Telescope Mount and Optics;30
4.2.3;2.2.3 Alternative Geometrical Configurations;33
4.3;2.3 Technological Challenges for Radio Telescopes;34
4.4;2.4 Basic Specifications of a Reflector Radio Telescope;35
4.4.1;2.4.1 Reflector Precision;36
4.4.2;2.4.2 Pointing Precision;36
4.5;2.5 Summary;37
4.6;Addendum: Geometry of Optical Configuration;38
4.7;References;42
5;Chapter 3: Birth of Radio Astronomy;43
5.1;3.1 Early History of Radio Telescopes;44
5.1.1;3.1.1 Jansky´s Bruce Antenna;44
5.1.2;3.1.2 Reber´s Transit Paraboloidal Reflector;44
5.1.3;3.1.3 Würzburg Riese Radar Antenna;46
5.2;3.2 The First Large Radio Telescopes;48
5.2.1;3.2.1 Dwingeloo (NL) and Stockert (BRD) Telescopes;49
5.2.1.1;3.2.1.1 Dwingeloo;49
5.2.1.2;3.2.1.2 Stockert;51
5.2.2;3.2.2 A Comment on Accessibility of the Focal Point;54
5.2.3;3.2.3 Jodrell Bank (UK): Lovell Telescope (76 m);54
5.2.4;3.2.4 Parkes (Australia) 64 m Telescope;59
5.2.5;3.2.5 NRAO (USA): 140-ft and 300-ft Telescopes;62
5.2.5.1;3.2.5.1 NRAO 140-ft Equatorial Telescope: An Expensive and Slow Project;64
5.2.5.2;3.2.5.2 NRAO 300-ft Transit Telescope: A Cheap and Quick Deal;67
5.2.6;3.2.6 The 120-ft Haystack Antenna of MIT Lincoln Laboratory;69
5.3;3.3 Conclusion;72
5.4;References;72
6;Chapter 4: Structural Design of Reflector Antennas: Homology;74
6.1;4.1 Introduction;75
6.2;4.2 The Design of Homologous Structures;75
6.3;4.3 The Design of a 65-m Homologous mm Telescope;81
6.4;4.4 The Effelsberg 100-m Radio Telescope;84
6.4.1;4.4.1 The German Proposal for a Giant Radio Telescope;84
6.4.2;4.4.2 A Comment on the Homologous Behaviour of a Structure;86
6.4.3;4.4.3 The Industrial Design Proposals;86
6.4.4;4.4.4 The Final Design and Realisation;89
6.5;4.5 Backup Structure and Deformation Patterns;91
6.5.1;4.5.1 The Design Approach of the Effelsberg Backup Structure;92
6.5.2;4.5.2 Interpretation of the Load Cases of the Effelsberg Reflector;95
6.5.2.1;4.5.2.1 Zenith Position;95
6.5.2.2;4.5.2.2 Horizon Position;96
6.5.3;4.5.3 Load Case Superposition;97
6.5.4;4.5.4 The Deformation Behaviour of the Effelsberg Reflector;98
6.5.5;4.5.5 Performance Limits of the Effelsberg Reflector Principle;103
6.6;4.6 Four-Point Reflector Support;106
6.6.1;4.6.1 Introduction;106
6.6.2;4.6.2 The Westerbork Array of 25-m Antennas;107
6.6.3;4.6.3 The MERLIN Antenna with a Perfect Four-Point Support;109
6.6.4;4.6.4 The Joined Four-Point Support of the IGN 40-m Telescope;114
6.7;4.7 Conclusion;117
6.8;References;117
7;Chapter 5: Emergence of Millimetre-Wavelength Telescopes;118
7.1;5.1 Into mm Wavelengths;119
7.2;5.2 The NRAO 36-ft Antenna;120
7.3;5.3 The IRAM 30-m Telescope (MRT);123
7.3.1;5.3.1 Introduction: Performance Specification;123
7.3.2;5.3.2 The Design Selection;125
7.3.3;5.3.3 The Structural Concept of the MRT;129
7.3.4;5.3.4 The Deformation Behaviour of the MRT;132
7.3.4.1;5.3.4.1 Load Case in Zenith Position;132
7.3.4.2;5.3.4.2 Load Case in Horizon Position;133
7.3.4.3;5.3.4.3 The Deformation Behaviour of the Final Improved Design;133
7.3.5;5.3.5 Overall Surface Error of the Actual Telescope;136
7.3.6;5.3.6 Thermal Effects and Their Control;137
7.3.7;5.3.7 Conclusion;142
7.4;5.4 The Large Millimeter Telescope;143
7.4.1;5.4.1 Conceptual Design Phase;143
7.4.2;5.4.2 Towards a Final LMT Design;146
7.4.3;5.4.3 The Final Design of the LMT/GTM;147
7.4.4;5.4.4 Short Review of Surface Panel Technology;150
7.4.5;5.4.5 The Isostatic Reflector Segments of the LMT;151
7.4.6;5.4.6 Flexible Body Control (FBC);152
7.4.7;5.4.7 Concluding Remark on the LMT/GTM;154
7.5;5.5 The Nobeyama 45-m Millimeter Telescope;155
7.6;5.6 Conclusion;156
7.7;Addendum: Thermal Effects and Their Control;156
7.8;References;162
8;Chapter 6: Submillimetre-Wavelength Telescopes;164
8.1;6.1 Introduction;165
8.2;6.2 Leighton Dish and CSO Telescope;166
8.3;6.3 CFRP Telescopes: IRAM 15-m and HHT;168
8.3.1;6.3.1 The IRAM Interferometer Antennas;168
8.3.2;6.3.2 The Heinrich Hertz (Submillimeter) Telescope (HHT);170
8.4;6.4 Atacama Large Millimeter Array (ALMA) Antennas;173
8.4.1;6.4.1 Introduction;173
8.4.2;6.4.2 Test Program and Performance of the ALMA Prototype Antennas;176
8.4.3;6.4.3 Remark on the Circular BUS/ELC Interface Concept;179
8.4.4;6.4.4 Comparison of the Designs from AEM/EIE and Vertex;181
8.4.4.1;6.4.4.1 Comparison of Structural Design;181
8.4.4.2;6.4.4.2 Weight;184
8.4.4.3;6.4.4.3 Deformation Behaviour;185
8.4.4.4;6.4.4.4 Interpretation of the Astigmatism from Basic Structural Mechanics;186
8.4.4.5;6.4.4.5 Comparison of the Bearing and Drive Systems;190
8.4.4.6;6.4.4.6 Dynamic Behaviour, Structural Resonance Frequencies;191
8.4.5;6.4.5 Conclusion;192
8.5;References;194
9;Chapter 7: Alternative Reflector Geometries;195
9.1;7.1 Telescopes with Fixed Main Reflectors;196
9.2;7.2 The Giant Metrewave Radio Telescope (GMRT) in India;200
9.3;7.3 Large Horn Antennas;201
9.4;7.4 Offset Reflector Antennas;202
9.4.1;7.4.1 Introduction;202
9.4.2;7.4.2 Allen Telescope Array (ATA);204
9.4.3;7.4.3 MeerKAT and Square Kilometre Array (SKA);205
9.4.4;7.4.4 Green Bank Telescope (GBT);208
9.5;Addendum: Remarks on Wheel-On-Track Systems;213
9.6;References;217
10;Chapter 8: Electromagnetic Aspects of the Reflector Antenna;218
10.1;8.1 Introduction;219
10.2;8.2 Radiation Pattern of a Circular Aperture;220
10.3;8.3 Major Parameters of the Reflector Antenna;222
10.4;8.4 Influence of Imperfections on Performance;224
10.4.1;8.4.1 Illumination, Spillover and Polarisation Efficiency;224
10.4.2;8.4.2 Radiation Efficiency;226
10.4.3;8.4.3 Small-Scale Surface Error (Scattering) Efficiency;226
10.4.4;8.4.4 Large-Scale Deformation: Representation by Zernike Polynomials;229
10.4.5;8.4.5 Blocking Efficiency;231
10.4.6;8.4.6 Lateral and Axial Defocus: Gain Loss;233
10.4.7;8.4.7 Beam Deviation Factor (BDF);236
10.4.8;8.4.8 Conclusion;236
10.5;8.5 Measuring Antenna Parameters with Cosmic Sources;237
10.5.1;8.5.1 Antenna Gain and Beam Pattern;237
10.5.2;8.5.2 Antenna Pointing;238
10.6;8.6 Radio Holographic Measurement of Reflector Profile;240
10.7;8.7 Progress in Electromagnetic Design;242
10.7.1;8.7.1 Historical Introduction;242
10.7.2;8.7.2 Radio Astronomy and Communication Approaches Differ;243
10.7.3;8.7.3 Exploiting the Focal Plane;244
10.7.3.1;8.7.3.1 Multi-feed System with Independent Pixels;244
10.7.3.2;8.7.3.2 Phased-Array Feeds (PAF);245
10.8;8.8 Conclusion;246
10.9;Addendum: Aberrations and Zernike Polynomials;247
10.10;References;250
11;Chapter 9: Concluding Review and a Dialogue on Management Aspects;252
11.1;9.1 Concluding Review;253
11.2;9.2 A Dialogue on Management Aspects;260
11.2.1;9.2.1 Customer and Contractor;261
11.2.2;9.2.2 Project Management and System Engineering;262
11.2.3;9.2.3 Technological Aspects;263
11.2.4;9.2.4 Industrialisation Aspects, Costs;264
11.2.5;9.2.5 Manufacturing in Foreign Countries;265
11.2.6;9.2.6 Product Delivery, Commissioning;266
12;Acronyms and Abbreviations;268
13;Glossary;271
14;Name Index;274
15;Subject Index;278