by Trueblood and Genet
6 by 9 inches, 562 pages, hardbound, 183 figures,
$29.95.
About this book:
Computer control has spread to so many industries that many system components, such as motor controller boards for the PC-clone, Macintosh, and UNIX workstation are now available commercially.
In the previous edition of this book, the authors included several circuit schematic diagrams for custom electronics to perform functions that can now be performed by off-the-shelf circuitry. Many of these boards are affordable by amateurs and can save a great deal of time in developing a system. In this book, you will see fewer electronic schematics and more examples of how to use off-the-shelf boards and subsystems to configure your control system quickly.
This book still fills a gap in the books that are available on using personal computers in astronomical applications. Most of the other books stress computing that can be done at the leisure of both the hobbyist and the computer, and computing that uses only the basic computer and standard peripheral devices (disks, printers, etc.) as they come from the computer store. Image processing and orbit computing are examples of this type of computing.
This book is primarily concerned with how to connect a non-standard computer peripheral device (a telescope) to a computer and how to program the computer to perform time-critical computations. This is only one example of the more general problem of real-time control, so if viewed in this larger context, this book should find an audience among those interested in any real-time control application, such as robotics.
From the Reviewers
Telescope Control contains a wealth of information for the reader with some knowledge of electronics and software who wants to build a computerised telescope, and I can throuroughly recommend it.
—Journal of the British Astronomical Association
Table of Contents
Chapter 1 Introduction
1.1 Overview
1.2 Organization of Topics
Part I Why and How to Computerize a Telescope
Chapter 2 Why Control Telescopes With Computers?
2.1 Reasons for Computerized Telescope Control
2.2 Cost/Benefit Reasons
2.3 Modern Observing Methods
Chapter 3 Modern Systems Engineering
3.1 The Project Life Cycle
3.2 Defining Your System's Requirements
3.2.1 Portability
3.2.2 Setup Time
3.2.3 Optics
3.2.4 Telescope Pointing Accuracy
3.2.5 Telescope Pointing Time
3.2.6 Long Term Tracking Accuracy
3.2.7 Short Term Tracking Accuracy
3.2.8 Data Input and Control Devices
3.2.9 Computer Environment
3.2.10 Commands
3.2.11 Extraneous Light Control
3.3 Designing Your System
3.3.1 Method of Transport
3.3.2 Telescope Mount Type
3.3.3 Optical System
3.3.4 Drive Design Approach
3.3.5 Control System Approach
3.3.6 Computational Requirements
3.3.7 Computer Hardware and Software
3.3.7.1 Processor Speed
3.3.7.2 Arithmetic Hardware
3.3.7.3 Interrupt Hardware
3.3.7.4 Standard Bus Structure
3.3.7.5 Development Environment
3.3.7.6 Operating System
Part II Telescope Control System Design Considerations
Chapter 4 An Introduction to Control Theory
4.1 Control Options
4.2 The Role of Position Feedback
4.3 Equation of Motion
4.4 The Role of Velocity Feedback
4.5 Matching the Telescope and the Control System
Chapter 5 Systematic Errors I — Astronomical Corrections
5.1 Precession
5.1.1 The Physical Basis of Precession
5.1.2 Magnitude of the Precession Corrections
5.1.3 Computing General Precession
5.2 Nutation
5.2.1 The Physical Basis of Nutation
5.2.2 Magnitude of the Nutation Corrections
5.2.3 Computing Nutation
5.3 Polar Motion
5.4 Sidereal Time
5.4.1 About Time
5.4.2 Magnitude of Time Corrections
5.4.3 Computing Sidereal Time
5.5 Aberration
5.5.1 The Physical Basis of Aberration
5.5.2 Magnitude of Stellar Aberration Corrections
5.5.3 Computing Annual Aberration
5.5.4 Computing Diurnal Aberration
5.5.5 General Relativistic Effects
5.6 Parallax
5.6.1 The Physical Basis of Parallax
5.6.2 Magnitude of Parallax Corrections
5.6.3 Computing Stellar Parallax
5.6.4 Computing Solar or Planetary Parallax
5.7 Refraction
5.7.1 The Physical Basis of Refraction
5.7.2 Magnitude of Refraction Corrections
5.7.3 Computing Refraction
5.7.4 Parallactic Refraction
5.8 Orbital Motion
5.9 Proper Motion
5.10 Reduction from Mean to Topocentric Place
5.11 Changes in the 1984 Ephemerides
Chapter 6 Systematic Errors II — Mechanical Corrections
6.1 Telescope Mount Designs
6.2 Telescope Pointing Corrections—Equatorial Mount
6.2.1 Zero Offset
6.2.2 Polar Axis Alignment
6.2.3 Driving Rates
6.3 Telescope Pointing Corrections—Alt-Az Mount
6.3.1 Zero Offset
6.3.2 Azimuth Axis Alignment
6.3.3 Equatorial to Alt-Az Conversion
6.3.3.1 Conversion Equations
6.3.3.2 Driving Rates
6.3.3.3 Field Rotation Corrections
6.4 Telescope Pointing Corrections—Alt-Alt Mount
6.4.1 Zero Offset
6.4.2 North-South Axis Alignment
6.4.3 Equatorial to Alt-Alt Conversion
6.4.3.1 Conversion Equations
6.4.3.2 Driving Rates
6.4.3.3 Field Rotation Corrections
6.5 Intrinsic Telescope Corrections
6.5.1 Non-Perpendicular Axis Alignment
6.5.2 Non-Alignment of Mechanical and Optical Axes
6.5.3 Tube Flexure
6.5.4 Mount Flexure
6.5.5 Servo Lag Errors
6.5.6 Position Encoder Errors
6.5.7 Gearing Errors
6.5.8 Bearing Errors
6.5.9 Drive Train Torsion Errors
6.6 Reducing the Effects of Systematic Errors
6.6.1 Mechanical Adjustments
6.6.2 Compensating for Mechanical Behavior in Software
Chapter 7 Practical Design Considerations
7.1 Operator Convenience
7.2 Hardware/Software Tradeoffs
7.3 Single Board Computers and Buses
7.4 Hardware Approaches
7.5 Interface Software
7.6 Adaptability
7.7 Reliability
7.8 Maintainability
7.9 Safety
7.10 Conclusions
Part III Telescope Control System Components
Chapter 8 Motors and Motor Controllers
8.1 A Standard Telescope Problem
8.2 Large DC Torque Motors
8.3 Servo Motors
8.4 Servo Motor Controllers and Computer Interfaces
8.5 Stepper Motors
8.6 Stepper Motor Controllers and Computer Interfaces
Chapter 9 Sensors
9.1 Precision Potentiometers
9.2 Variable Reluctance Transformers
9.3 Resolvers
9.4 Synchros
9.5 Inductosyns
9.6 Rotary Differential Capacitors
9.7 Optical Shaft Angle Encoders
9.8 Other Encoder Types
9.9 Time Code Receivers
9.10 Other Useful Sensors
Chapter 10 The Operator Interface
10.1 Types of Operator Interfaces
10.2 Characteristics of a Good Operator Interface
10.3 Design of Graphical User Interfaces
Chapter 11 Computers and System Software
11.1 Characteristics of Real-Time Command and Control
11.2 Selecting Computer Hardware
11.3 Selecting the Operating System
11.4 Selecting the Development Environment
Part IV Examples of Telescope Control Systems
Chapter 12 The Phoenix IV Telescope Control System
12.1 History of the Phoenix IV Telescope
12.2 Drive Train
12.2.1 Electronic
12.2.2 Software
12.2.3 Development History
12.3 A Platform-Independent Approach
12.3.1 The Nyden Motion Controller
12.3.1 The Nyden Motion Controller
12.3.2 Bi-Polar Chopper Stepper Translators
12.3.3 Analog Joystick
12.3.4 Software
Chapter 13 The WMO Telescope Control System
13.1 The WMO Observing Program
13.2 System Operational Environment
13.3 System Performance Requirements
13.3.1 Portability
13.3.2 Setup Time
13.3.3 Optics
13.3.4 Telescope Pointing Accuracy
13.3.5 Telescope Pointing Time
13.3.6 Long Term Tracking Accuracy
13.3.7 Short Term Tracking Accuracy
13.3.8 Data Input and Control Device
13.3.9 Computer Environment
13.3.10 Commands
13.3.11 Extraneous Light Control
13.4 Overall System Design and Evolution
13.4.1 Method of Transport
13.4.2 Telescope Mount Type
13.4.3 Optical System
13.4.4 Drive Design Approach
13.4.5 Control System Approach
13.4.6 Top Level System Design
13.5 Position Encoder Calibration
13.6 Computational Requirements
13.6.1 Topocentric Place Correction
13.6.1.1 General Precession
13.6.1.2 Nutation
13.6.1.3 Aberration
13.6.1.4 Parallax
13.6.1.5 Refraction
13.6.1.6 Orbital Motion
13.6.1.7 Proper Motion
13.6.2 Mechanical Corrections
13.6.2.1 Conversion of the Encoder Reading
13.6.2.2 Zero Offset
13.6.2.3 Polar Axis Alignment
13.6.2.4 Azimuth Axis Alignment
13.6.2.5 Equatorial to Alt-Az Conversion
13.6.2.6 Nonperpendicular Axis Alignment
13.6.2.7 Collimation Errors
13.6.2.8 Tube Flexure
13.6.2.9 Mount Flexure
13.6.2.10 Servo Lag Error
13.6.3 Processor Loading Calculations
13.7 Selection of the Development and Control System Environments
13.8 System Development and Evolution
13.9 Detailed Servo Design
13.10 Drive Train Design
13.10.1 Drive Train Mechanical Design
13.10.2 Motor and Motor Gearing Selection
13.10.3 Motor Controller Computer Interface Selection
13.10.4 Position Encoder Selection
13.10.5 Position Encoder Computer Interface Selection
13.11 Computer System Hardware
13.11.1 Control Computer
13.11.2 Operator Interface
13.11.3 Telescope Drive
13.11.4 High Speed Photometer
13.12 Software Design
13.12.1 Operational Considerations
13.12.2 Top-Level Software Design
13.13 Assessment of System Performance Reqirements
13.13.1 Portability
13.13.2 Setup Time
13.13.3 Optics
13.13.4 Telescope Pointing Accuracy
13.13.5 Telescope Pointing Time
13.13.6 Long Term Tracking Accuracy
13.13.7 Short Term Tracking Accuracy
13.13.8 Data Input and Control Device
13.13.9 Computer Environment
13.13.10 Commands
13.13.11 Extraneous Light Control
Chapter 14 Professional and Commercial Telescope Control Systems
14.1 The Keck 10-m Telescope Control System
14.2 ACE PC-Based Control System
14.3 AB Engineering
14.4 COMSOFT PC-TCS
14.5 Soft-Tec Systems
14.6 EPICS
14.7 Gemini 8-meter Telescopes Control System
14.8 Indiana University Control System
14.9 Quadrant Systems
Part V Robotic Telescope Control
Chapter 15 Automatic Photoelectric Telescopes (APTs)
15.1 Robotic Telescopes
15.2 Automatic Photoelectric Telescopes (APTs)
15.3 Astronomical Considerations
15.4 The Telescope
15.5 Mount and Drives
15.6 Control System
15.7 Background of the APT Project
Chapter 16 Basic APT Control Hardware
16.1 Introduction
16.2 Telescope Mount and Drive
16.3 Control System Hardware
16.3.1 System Block Diagram
16.3.2 PT69 Computer
16.3.3 Telescope Control Board
16.3.4 Stepper Drivers
16.3.5 Hand Paddle
Chapter 17 Basic APT Control Software
17.1 Introduction
17.2 Elementary Software
17.3 APT Software Functions and Subprograms
17.3.1 MAIN
17.3.2 Build Rise/Set Time Table
17.3.3 Open Output File
17.3.4 Initialize Telescope
17.3.5 Determine Which Group to Observe
17.3.6 Check Moon
17.3.7 Move to Group
17.3.8 Hunt and Lock
17.3.9 Make Photoelectric Measurements
17.3.10 Store Measurements
17.3.11 Evaluate Group Data
17.4 APT Supporting Procedures and Files
17.4.1 COEFFICIENTS
17.4.2 DIGITAL
17.4.3 HELIO
17.4.4 HUNT
17.4.5 LOCK
7.4.6 LUNAR
17.4.7 MEAS
17.4.8 MOVE
17.4.9 PRECESS
17.4.10 PTLCK
17.4.11 RAMP
17.4.12 SHOCO
17.4.13 SOLAR
17.4.14 STARFILE
17.4.15 STARTSCOPE
17.4.16 STOPSCOPE
17.4.17 SUNANGLE
17.4.18 THRESH
17.4.19 TIME
17.4.20 TRAVEL
17.4.21 ZENITH
17.5 Auxiliary Procedures
17.5.1 BUILDFILE
17.5.2 DATREAD
17.5.3 JOY4
17.5.4 MANCO
17.5.5 SET
17.5.6 SHOWTIM
17.5.7 TILDARK
17.5.8 TRANSFORM
Chapter 18 Advanced Robotic Telescope Control
18.1 The Normal Growth of Complexity and Specialization
18.2 Automatic Telescope Instruction Set (ATIS)
18.3 Centering and Finding Stars
18.4 Improved Accuracy and Quality Control
18.5 Fully Automated CCD Photometry
18.6 Fully Automated Stellar Spectroscopy
18.7 Networked Robotic Telescopes
18.8 AI-Based Operations
18.9 The Future of Robotic Telescope Control
Appendix A Telescope Control System Costs
Appendix B Manufacturers of Motors and Related Hardware
Appendix C Manufacturers of Position Sensors
Appendix D Manufacturers of PC-Clone Products
Appendix E Manufacturers of Items Related to Telescope Control
Appendix F APT Control Algorithms
F.1 Introduction
F.2 Computer Mathematics
F.3 Modified Julian Date
F.4 Local Mean Sidereal Time
F.5 Position of the Sun
F.6 Position of the Moon
F.7 Zenith Angle
F.8 Heliocentric Correction
F.9 Precession to Current Coordinates
F.10 Determination of Observability of a Star
Appendix G Automatic Photoelectric Telescope Software
Appendix H Phoenix IV Control Software
Appendix I Calibrating Encoders Using Kalman Filtering
I.1 Weighted Least Squares
I.2 Kalman Filter
I.3 Extended Kalman Filter
Appendix Glossary
Bibliography
Index