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Book 0004.Pdf 2 VLT Whitebook - List of Contents Introduction 9 Executive Summary 1. VLT Concepts and Performance 12 1.1 Scientific Objectives and Technical Requirements 12 1.2 Implementation and Future Optimization 13 1.3 Performance Requirements 14 1.4 The VLT Interferometer (VLTI) 16 1.5 Instrumentation 18 1.6 Science Operations 19 1.7 Data Archive and Distribution 20 2. Main Elements 21 2.1 Unit 8.2-m Telescope 22 2.2 The Main Mirrors (M1, M2 and M3) 24 2.3 Active and Adaptive Optics 26 2.3.1 Active Optics 26 2.3.2 Adaptive Optics 28 2.4 Array Configuration 29 2.5 Beam Combination and Interferometry 31 2.6 Instrumentation Package 32 2.6.1 VLT Instrumentation Projects 33 2.6.2 Observational Strategy 34 2.6.3 Observational Domains 35 2.6.4 Detectors 36 2.6.5 Spectroscopic Modes 36 2.6.6 Imagery 37 2.7 The Enclosures 38 2.7.1 Basic Functions 38 2.7.2 Design 39 3 2.7.3 Environmental Control 40 2.8 The Paranal Observatory 42 2.8.1 Infrastructure 42 2.8.2 Geographical Data 44 2.8.3 Observing Conditions 45 2.8.4 Seismics 49 2.9 The VLT End-to-End Model 51 2.9.1 Components 52 2.9.2 Model Architecture 53 3. The Optics 55 3.1 Concept 57 3.1.1. Optical Quality 59 3.1.2. Operating conditions 60 3.2 The Primary Mirror 61 3.2.1 Specifications 61 3.2.2 The Manufacturing Process 62 3.2.3 Mirror characteristics 63 3.3 The Secondary Mirror 67 3.3.1 Specifications 67 3.3.2 The Manufacturing Process 69 3.3.3 Mirror Characteristics 70 3.4 The Nasmyth Mirror 71 3.4.1 Specifications 71 3.4.2 M3 Hydraulic Support System 72 3.4.3 Manufacturing of the M3 Blanks 72 3.4.4 Mirror Characteristics 73 3.5 Sky Baffling and Pupil Alignment 74 3.6 The Cassegrain Focus 75 3.6.1 Optical Design 75 3.6.2 Cassegrain Adapter-Rotator 76 3.6.3 Instrument Interface 76 3.7 The Nasmyth Focus 77 3.7.1 Optical Design 77 3.7.2 Nasmyth Adapter-Rotator 78 4 3.7.3 Instrument Interface 81 3.8 The Coudé Focus 82 3.9 Coating 84 3.9.1 Concept 84 3.9.2 Implementation 84 3.10 Polarimetry 86 4. M1 Cell and M3 Tower 87 4.1 The Concepts 88 4.2 M1 Cell 90 4.2.1 M1 axial support system 91 4.2.2 M1 lateral support system 94 4.3 M3 Unit 95 4.4 Control System 97 4.5 Thermal Control 98 5. M2 Unit 99 5.1 Main Functions 100 5.2 Functional Assemblies 102 5.3 Specifications 104 6. Main Structure 107 6.1 Main Components 108 6.2 Performance 110 6.2.1 Stiffness and Eigenfrequencies 110 6.3 Bearings 112 6.4 Drives 113 6.5 Encoders 114 6.5.1 Design Goals 114 6.5.2 Implementation 115 6.6 Pointing and Tracking 116 6.6.1 Design Goals 116 6.6.2 Implementation 116 6.7 Nasmyth 117 5 7. Control Software 119 7.1 Distributed Architecture - Networks 120 7.1.1 Logical Lay-out 120 7.1.2 LAN Requirements 120 7.1.3 Test Camera on UT1 121 7.2 The VLT Common Software (VCS) 122 7.3 Hardware 123 7.4 Time Keeping 124 7.5 Central Control Software 125 7.6 Telescope Coordination Software 126 7.7 Instrument Processes 127 7.7.1 Observation Software 127 7.7.2 Detector Control Software 127 7.7.3 Real Time Display 128 7.8 Integration of the VLT Control and Data Flow Software 129 7.8.1 Requirements for the VLT Control Software 129 7.8.2 The High Level View: Observation Blocks 129 7.8.3 Templates 130 7.8.4 Broker for Observation Blocks 130 8. Instrumentation 133 8.1 Concepts and Scientific Drivers 133 8.2 Optical region (300 - 1000 nm) 135 8.2.1 FORS 135 8.2.2 UVES 141 8.2.3 FLAMES 145 8.2.4 VIMOS 147 8.3 Near-IR Region (1 - 5 µm) 150 8.3.1 ISAAC 150 8.3.2 CONICA 155 8.3.3 CRIRES 159 8.3.4 NIRMOS 164 8.3.5 SINFONI 167 8.4 Mid-IR Region (8 - 25 µm) 169 8.4.1 VISIR 169 6 8.5 NAOS - Nasmyth Adaptive Optics System 173 8.5.1 NAOS Concept and Scientific Drivers 173 8.5.2 NAOS preliminary performance 175 8.5.3 Status 178 8.6 MACAO - Multiple Application Curvature Adaptive Optics 179 8.6.1 The MACAO Concept 179 8.6.2 Technical Description 179 8.6.3 Performance Simulations 181 8.7 Laser Guide Star 182 8.8 Visitor Instruments 184 9. Interferometry 185 9.1 Concepts and Implementation Plan 186 9.1.1 VLTI Development 186 9.1.2 Implications 187 9.2 Scientific Goals 190 9.2.1 Extrasolar Planets 190 9.2.2 Low Mass Stars and Brown Dwarfs 191 9.2.3 Star Formation and Early Stellar Evolution 191 9.2.4 Stellar Surface Structure 192 9.2.5 Be stars 193 9.2.6 AGB stars 194 9.2.7 The Galactic Centre 195 9.2.8 Active Galactic Nuclei 196 9.3 UT Coudé Trains 197 9.4 Auxiliary Telescopes and Stations 198 9.5 Delay Lines 199 9.6 Beam Combination and Fringe 201 9.7 Instruments 202 9.7.1 AMBER 202 9.7.2 MIDI 205 9.7.3 PRIMA 210 9.8 Control System 211 9.8.1 Control Hardware 211 9.8.2 Control Software 212 7 10. Science Operations and VLT Data Flow 213 10.1 Concepts 214 10.1.1 High-Level Requirements 215 10.1.2 Services and Products 215 10.1.3 Operation Modes 215 10.2 Data Flow Overview 218 10.2.1 Programme Handling 218 10.2.3 OB Execution 219 10.2.4 Archiving 219 10.2.5 Pipeline 219 10.2.6 Quality Control 220 10.2.7 Data Format and Units 220 10.3 Programme Handling (Phase 1) 221 10.3.1 Proposal Preparation 221 10.3.2 Proposal Processing 222 10.4 Observation Handling (Phase 2) 224 10.4.1 Proposal Preparation 224 10.4.2 OB Processing 226 10.5 Scheduling and Execution of Observing Blocks 227 10.5.1 Scheduling Considerations 227 10.5.2 Execution of Observing Blocks 228 10.6 Pipeline Processing and Quality Control 230 10.6.1 Calibration 230 10.6.2 Quality Control 231 10.6.3 Instrument Models for Calibration and Quality Control 233 10.7 Archiving and Distribution 235 10.7.1 Basic Considerations 235 10.7.2 System Components 236 10.7.3 The Science Archive Research Environment 237 10.7.4 Access to Catalogs and Survey Data 238 Appendix 239 8 VLT Whitebook: Introduction The publication of the VLT Whitebook is part of a general effort by ESO to inform the astronomical user community of the member states about the basic concepts which have guided the design and development of the hardware and operating systems of the VLT/VLTI project and of the new observatory on Paranal. As the complexity of individual telescopes and their related instrumentation keeps growing, it is difficult even for the professional astronomer to be intimately conversant with all of the details which will permit the most effective utilization of the facility. In addition to direct experience at the telescopes used in all their different modes, it will be necessary to develop, both in the ESO Staff and in the user community, an in-depth working knowledge of the most effective observing strategies. While this overall description of VLT/VLTI and Paranal can not be carried out to the depth required by the specialist, it is intended to give a solid overview of the baseline configuration of telescopes, instruments and operating systems. We conceive of the VLT/VLTI telescope array and all auxiliary facilities on Paranal as the observing element of an institutional structure intended to offer European Astronomers up-to- date facilities to do science. Some of the elements necessary for the operation of this structure are embodied by operational units at ESO's Headquarters in Germany as well as in Chile. In particular, proposal solicitation and evaluation, program selection, initial programme schedule, as well as observing block preparation and transmittal to Paranal for execution are carried out at Garching. Detailed scheduling, support to astronomers in either service or visitors mode, real time diagnostics and optimization of the observations occur on Paranal. ESO in Chile also provides logistic support including transportation and housing for visiting astronomers. Data are reduced and stored in the ESO archive at Garching and from there distributed to the observers. This distributed approach to the execution of the functions is common to the La Silla and Paranal observatories. Also common is the development of detectors, instruments and software. This permits a very efficient use of our resources. Communications between the different functional groups is essential for the effective and successful completion of the scientific programmes. It is important for the best results that not only the ESO Staff, but the full user community, be appraised of our procedures and schedules. This new powerful facility on Paranal clearly gives the European Astronomical Community a fully competitive tool in ground based optical astronomy for the first time in this century.
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