The Dobsonian Telescope: A Practical Manual for Building Large Aperture Telescopes

The Dobsonian Telescope: A Practical Manual for Building Large Aperture Telescopes

£35.00✓ 2 year warranty


Out of stock due 60-90 working days

About this product

Model:  willbell_9780943396552
Part Number:  WBDT

The Dobsonian Telescope, A Practical Manual for Building Large Aperture Telescopes

Authors: David Kriege and Richard Berry

  • 15.2cm x 22.9cm, 496 pages, hardbound, 179 pictures, 88 drawings and 34 tables.

The Dobsonian Telescope, A Practical Manual for Building Large Aperture Telescopes tells how you can build a state-of-the-art Dobsonian telescope using readily available materials and supplies. Every step of construction is detailed in photographs and diagrams, and the underlying ideas are carefully explained. As a result of this three-year collaboration between authors David Kriege and Richard Berry, experienced and well-known telescope makers, you now have the opportunity to build a high-performance telescope from 14 inches to 40 inches aperture based on the thoroughly tested designs described in this book.

 The Dobsonian telescope takes its name from the astronomer/philosopher John Dobson, who introduced the concept of inexpensive, large-aperture telescopes to astronomy. Amateur astronomers at the time were so amazed that a telescope built from simple, inexpensive materials performed so well that they could hardly believe their eyes. As home-built Dobsonians started showing up at star parties across the nation and people saw what Dobsonians could do, the word spread. In just a few years, the Dobsonian revolution swept the world.

 Since those early telescopes, Dobsonians have improved dramatically. An entire generation of amateur telescope makers contributed their best insights and refinements to Dobson's original design. Today's Dobsonians are larger, lighter, and more precise than ever before. For example, it is possible to build a telescope of 20 inches aperture that is compact enough to transport in a hatchback automobile, yet takes only ten minutes to set up at a remote, dark-sky observing site.

 Deep-sky observers especially appreciate Dobsonian telescopes. With the 20-inch (50 centimeter) aperture that the authors recommend for first-time Dobsonian builders, hundreds of globular clusters, thousands of nebulae, and tens of thousands of galaxies are visible through the eyepiece. Planetary observers have discovered that from good observing sites, Dobsonians deliver breathtaking performance on the moon and planets. For the casual stargazer, familiar objects like the Hercules Cluster, the Great Nebula in Orion, the Lagoon Nebula, and the galaxies of the Virgo Cluster are an entirely new experience.

 Here are some of the topics covered in this book:

  • Deciding what size telescope will suit your needs
  • Ordering optics for a large Dobsonian
  • Understanding plywood and how to use it properly
  • Making a flotation cell to support the primary mirror
  • Figuring how long to cut the poles for the truss tube
  • Constructing precision truss tube sockets
  • Performing torque analysis for first-time balance
  • Installing precision digital setting circles
  • Setting up and taking down the telescope
  • How to collimate your optics correctly

 Whether you have never observed before or whether you have been an amateur astronomer all your life, you will benefit from the hands-on familiarity and experience in amateur astronomy and telescope making that the authors bring to this book.


This book is full of exceptionally useful advice and ideas, and is not only for those planning to build a telescope from scratch, but for anyone with a Dobsonian telescope of whatever design, who wants to see how they could improve its workings.(Astronomy & Space magazine)

If you ever wanted to build a really large telescope, the cornucopia of information the The Dobsonian Telescope will prove indispensable. Overall The Dobsonian Telescope is a terrific volume and wonderful accomplishment with little to criticise. It belongs on the shelf of every amateur telescope maker, and for that matter every Dobsonian owner. With its whimsical style and thorough treatment of the subject the book is destine to become a classic along with Albert Ingalls's Amateur Telescope Making and Jean Texereau's How to Make a Telescope.(Sky & Telescope magazine)

Table of Contents

Chapter 1 Large Aperture Dobsonians 
   1.1 Why Dobsonians Are Newtonians 
   1.2 How Dobsonians Work 
   1.3 The History of the Dobsonian Telescope 
         1.3.1 John Dobson Invents the Dobsonian 
         1.3.2 The Dobsonian Revolution 
         1.3.4 The Second Dobsonian Revolution 
1.4 The Dobsonian in Your Future 
Chapter 2 Planning Your Telescope 
     2.1 Non-Telescopic Telescope Considerations 
     2.2 Tough Telescopic Considerations 
         2.2.1 Telescope Aperture Considerations 
         2.2.2 Are You Obsessed? 
     2.3 How To Get Started 
Chapter 3 Engineering the Dobsonian 
     3.1 Engineering for Performance 
     3.2 Statics: How to Make a Stiff Telescope 
         3.2.1 Engineering Terms 
         3.2.2 The Moment of Inertia 
         3.2.3 Elastic Deformation
         3.2.4 The Strength of Materials 
         3.2.5 Stiffness of a Truss Pole 
         Flexure in the Rocker Box 
         Flexure of a Telescope Mirror 
         Why Simple Scaling Doesn't Work 
         3.2.6 Dobsonian Dynamics: How Dobsonians Move 
         Balancing a Dobsonian 
         3.2.7 Friction in a Dobsonian 
         Friction Defined 
         Dobsonian Friction 
         Curing Stiction 
         3.3 Materials for Telescopes 
                  3.3.1 Wood 
                  Wood Is a Natural, Organic Composite 
                  Wood Is Orthotropic 
                  Selecting Wood 
                  3.3.2 Aluminum 
                  3.3.3 Teflon 
                  3.3.4 Plastic Laminates 
                  "Ebony Star" and "Stardust" Laminates 
                  Put Car Wax on Laminates 
      3.4 Protective Coatings 
Chapter 4 Optics for Dobsonians 
      4.1 Basic Newtonian Optics 
      4.2 Choosing the Mirror 
                  4.2.1 Choice 1: What Aperture? 
                  4.2.2 Choice 2: What Focal Ratio? 
                  4.2.3 Choice 3: Make or Buy? 
                  4.2.4 Choice 4: What Glass? 
                  4.2.5 Choice 5: Cut Sheet or Molded Blanks? 
                  4.2.6 Choice 6: Fine or Precision Annealed? 
                  4.2.7 Choice 7: How Thick? 
                  4.2.8 Choice 8: Blanchard Ground? 
                  4.2.9 Choice 9: What Coatings? 
                  4.2.10 Choice 10: Optical Quality 
      4.3 Thinking About Eyepieces 
      4.4 Thinking About the Focuser 
      4.5 Sizing the Secondary Mirror 
      4.6 To Offset or Not to Offset? 
      4.7 Testing Telescope Optics 
      4.8 What To Do If You Don't Like a Mirror 
Chapter 5 The Primary Mirror Cell 
      5.1 The Flotation System and the Sling 
                  5.1.1 Flotation in Theory 
                  5.1.2 Flotation in Practice 
      5.2 Building the Flotation System 
                  5.2.1 Flotation System Design 
                           Material for Bars and Triangles 
                           Flotation System Pads 
         Build the Cell Subassemblies 
      5.3 The Tailgate 
                  5.3.1 Evolution of the Tailgate 
                  5.3.2 The Open-Frame Tailgate 
                  5.3.3 Tailgate Layouts 
                  5.3.4 Cutting Tailgate Materials 
                  5.3.5 Drill Holes Before Welding 
                  5.3.6 Weld Using a Jig 
      5.4 Mount the Tailgate in the Mirror Box 
                  5.4.1 Collimation Bolts 
                  5.4.2 Flotation System Hardware 
                  5.4.3 The Sling and Split Bolts 
                  5.4.4 Side Pins 
Chapter 6 The Secondary Cage 
      6.1 Dimensioning the Secondary Cage 
                  6.1.1 The Truss-Tube Advantage 
                  6.1.2 The Inside Diameter of the Secondary Cage 
      6.2 Constructing the Secondary Cage 
                  6.2.1 Order the Spider and Secondary Holder, and Focuser 
                  6.2.2 Cut the Rings 
                  6.2.3 Make Three Rings for "The Big Ones" 
                  6.2.4 Drill the Strut Seats 
                  6.2.5 Make the Struts 
                  6.2.6 Attach the Struts to the Rings 
                  6.2.7 The Focuser Board 
                  6.2.8 Install the Kydex Light Baffle 
      6.3 Connecting Ring for "The Big Ones" 
      6.4 Install the Hardware 
                  6.4.1 Install the Focuser 
Chapter 7 Building the Mirror Box 
      7.1 Holding It All Together 
                  7.1.1 Why the Mirror Box is Stubby 
      7.2 Mirror Box Materials 
      7.3 Designing the Mirror Box 
                  7.3.1 Height and Width of the Mirror Box 
                  7.3.2 How Balance Affects the Mirror Box 
                  7.3.3 Calculating the Balance Point 
                  7.3.4 The Depth of the Mirror Box 
      7.4 Balancing the Telescope 
      7.5 Split Blocks for the Mirror Box 
      7.6 The Side Bearings 
                  7.6.1 Making the Mirror Box 
                  7.6.2 Cutting the Sides 
                  7.6.3 The Light Baffle 
                  7.6.4 Assembling the Mirror Box 
                  7.6.5 Side Bearing Dimensions 
                  7.6.6 Bonding Flat Panels of Plywood 
                  7.6.7 Constructing the Side Bearings 
                  7.6.8 Placing the Side Bearings 
                  7.6.9 Mounting the Side Bearings 
      7.7 To Shortcut or Not To Shortcut? 
      7.8 The Dust Cover 
Chapter 8 The Truss Tube 
      8.1 How to Build a Serious Truss Tube 
                  8.1.1 Flexure in Truss Poles 
                  8.1.2 The Diameter of the Truss Poles 
                  8.1.3 The Length of the Truss Poles 
      8.2 Attaching Truss Poles to the Mirror Box 
                  8.2.1 Overview of Pole Sockets 
                  8.2.2 Wooden Split-Block Sockets 
                           How to Make Split-Block Sockets 
                           Simplified Split Block Sockets 
                           Fancy Cam-Action Pole Sockets 
                           Strap and Channel Sockets 
      8.3 How to Align Truss Pole Sockets 
      8.4 Attaching Truss Poles to the Secondary Cage 
                  8.4.1 The Crushed Tube Method 
                  8.4.2 The Threaded-Insert Method 
                  8.4.3 The Offset-Bracket Method 
                  8.4.4 The Seats and Wedges Method 
         Making Pole Seats 
         Making Pole Wedges 
Chapter 9 Bearings 
     9.1 How Dobsonian Bearings Work 
                  9.1.1 What is Friction? 
                  9.1.2 Friction in the Altitude Bearings 
                  9.1.3 Friction in the Azimuth Bearings 
Chapter 10 The Rocker and Ground Board 
     10.1 Sizing the Rocker 
     10.2 Rocker Construction 
                  10.2.1 Ground Board 
                  10.2.2 Ground Boards for "The Big Ones" 
     10.3 Constructing the Ground Board 
                  10.3.1 The Azimuth Pivot 
                  10.3.2 How to Make the Pivot Bolt 
                  10.3.3 Installing the Pivot Bolt 
                  10.3.4 Installing Teflon Bearing Pads 
         Calculating the Size of the Altitude Bearing Pads 
         Calculating the Size of the Azimuth Bearing Pads 
     10.4 A Handy Option: Bearing Locks 
     10.5 Handles for Portability 
                  10.5.1 "It Rolls On Air" 
                  10.5.2 Attaching Handles to the Rocker 
     10.6 Handling the Big Ones 
Chapter 11 Assembly and Troubleshooting 
     11.1 Last-Minute Preparations 
     11.2 Installing the Optics 
                  11.2.1 Center-Dot the Primary 
                  11.2.2 Center Dot the Secondary Mirror 
                  11.2.3 Install the Primary Mirror 
                  11.2.4 Install the Secondary Mirror 
                  11.2.5 Adjust the Sling 
                  11.2.6 Collimate the Optics 
     11.3 Set-Up, Use, and Take-Down 
                  11.3.1 Set Up 
                  11.3.2 Using the Telescope 
                           Bearing Surfaces 
                           Safety Precautions 
                  11.3.3 Take-Down 
     11.4 Cleaning the Optics 
     11.5 Troubleshooting 
                  11.5.1 Too Little Focus In-Travel 
                  11.5.2 Sticking Poles and Blocks 
                  11.5.3 Telescopes and Moisture 
Chapter 12 Using Big Dobsonians 
     12.1 Eyepieces 
     12.2 Filters 
     12.3 Finders 
                  12.3.1 The Telrad® Finder 
                  12.3.2 Finder Telescopes 
                  12.3.3 Get Two Finders 
                  12.3.4 Jumbo Finders 
                  12.3.5 Digital Setting Circles 
     12.4 Electrical Accessories 
                  12.4.1 Dew Zappers 
                  12.4.2 Heat Ropes 
                  12.4.3 Portable 12-Volt Power 
                  12.4.4 Marine Batteries 
                  12.4.5 Power on the Secondary Cage 
     12.5 Keeping Warm and Dry 
                  12.5.1 Warm Clothing 
                  12.5.2 Keep Warm with Heat Packs 
     12.6 Eliminating Stray Light 
                  12.6.1 The Light Shroud 
                           Sewing a Shroud 
                           Installing the Shroud 
                  12.6.2 Focuser Baffling 
                  12.6.3 The External Light Baffle 
                  12.6.4 The Tailgate Cover 
     12.7 Telescope Covers 
                  12.7.1 Mirror Box Dust Cover 
                  12.7.2 Hat Box for the Secondary Cage 
                  12.7.3 Secondary Mirror Cover 
                  12.7.4 The Telescope Cover 
     12.8 Dark Observing Sites 
                  12.8.1 Why You Need a Dark Site 
                  12.8.2 Site Selection 
                  12.8.3 Human Factors 
Chapter 13 Epilog: Making a Small Telescope 
     13.1 Materials You Need 
     13.2 Overview of Construction 
     13.3 Begin with the Tube 
                  13.3.1 The Primary Mirror Cell 
                  13.3.2 Locate the Mirror Cell 
                  13.3.3 Finish the Tube 
                  13.3.4 Add End Rings 
                  13.3.5 Assemble the Tube 
     13.4 The Mounting 
                  13.4.1 Build the Tube Cradle 
                  13.4.2 Side Bearings 
                  13.4.3 Locate the Tube Balance Point 
                  13.4.4 Construct the Rocker 
                  13.4.5 Make the Ground Board 
Appendix A Wood as a Structural Material 
     A.1 The Properties of Plywood 
                  A.1.1 Types of Plywood 
                  A.1.2 The Stiffness of Plywood 
     A.2 Selecting Plywood for Telescopes 
                  A.2.1 Hardwood Veneer Hardwood Core Plywoods (HVHC) 
                  A.2.2 Hardwood Veneer Softwood Core Plywoods (HVSC) 
                  A.2.3 Softwood Veneer Softwood Core Plywoods (SVSC) 
   A.2.4 Particle Board 
Appendix B Grinding, Polishing, and Figuring Large, Thin Mirrors 
     B.1 Obtaining a Mirror Blank 
                  B.1.1 Porthole Glass: the Classic Choice 
                  B.1.2 Pyrex Sheet Glass 
                  B.1.3 Choose the Mirror Diameter 
                  B.1.4 Choose the Mirror Thickness 
                  B.1.5 Choose the Focal Ratio 
     B.2 Grinding Tools 
                  B.2.1 Solid and Built-up Tools 
                  B.2.2 Segmented Tools 
     B.3 Prepare a Suitable Work Area 
     B.4 Preparing for Grinding 
                  B.4.1 Facing the Blank 
                  B.4.2 How to Prevent Astigmatism 
                  B.4.3 Bevel the Edge 
                  B.4.4 Grinding Strokes 
     B.5 Rough Grinding 
     B.6 Fine Grinding 
                  B.6.1 Fine Abrasives 
                  B.6.2 Getting a Sphere 
                  B.6.3 Going on to #220 
                  B.6.4 The Fine Side of Fine Grinding 
     B.7 Preparing to Polish 
                  B.7.1 Pitch 
                  B.7.2 Polishing Agents 
                  B.7.3 Pitch Base 
     B.8 Making the Pitch Lap 
                  B.8.1 Grooving the Lap 
                  B.8.2 Pressing the Lap 
     B.9 Polishing 
                  B.9.1 Judging the "Feel" of the Lap 
                  B.9.2 Holding the Lap 
                  B.9.3 Completing the Polish 
     B.10 Testing 
                  B.10.1 Test Stand and Testing Tunnel 
                  B.10.2 Begin Testing Early 
                  B.10.3 Testing for Astigmatism 
     B.11 Figuring 
                  B.11.1 Goals in Figuring 
                  B.11.2 Rating Telescope Mirrors 
                  B.11.3 Do the Best You Can 
     B.12 Test Methods 
                  B.12.1 Testing the Sphere 
                           B.12.2 The Sphere and the Paraboloid 
                           B.12.3 Star Testing 
                                  B.12.3.1 Doing a Star Test 
                                  B.12.3.2 Interpreting the Star Test 
                          B.14.4 Applying a Null Test 
                         B.14.5 Reading a Ronchi Screen 
      B.13 The Art of Figuring 24 
                  B.13.1 High, Low, Long, Short 
                  B.13.2 Figuring Laps 
                  B.13.3 Figuring Strokes 
                                  B.13.3.1 The Long, Straight, Central Stroke 
                                  B.13.3.2 The W Stroke 
                                 B.13.3.3 Tangential Strokes 
                                  B.13.3.4 Strokes for Small Polishers 
                  B.13.4 Correcting a Low Edge 
                  B.13.5 Correcting a Turned-Down Edge 
                  B.13.6 Correcting High Zones 
                  B.13.7 Correcting Low Zones 
     B.16 A Few Final Words 
Appendix C Digital Setting Circles 
     C.1 A Bit of History 
     C.2 How Digital Circles Work 
     C.3 Accurate Circles Need an Accurate Telescope 
     C.4 Installation 
                  C.4.1 Mounting the Azimuth Encoder 
                  C.4.2 Mounting the Altitude Encoder 
                  C.4.3 Mounting the Computer 
     C.5 General Advice 
Appendix D Equatorial Platforms 
Appendix E Resources and Suppliers 
     E.1 Aluminum tubing 
     E.2 Foam tube insulation 
     E.3 Double-sided tape 
     E.4 Specialty tools, knobs and latches 
     E.5 Threaded inserts 
     E.6 Levelers (collimation knobs) 
     E.7 Felt tabs and floor protector pads (mirror cell pads) 
     E.8 HVHC plywood (Hardwood Veneer Hardwood Core) 
     E.9 Sliders or cord locks and sling webbing 
     E.10 Heat ropes 
     E.11 Heat paks 
     E.12 Black Ripstop Nylon (for the light shroud) 
     E.13 Kydex plastic for the light baffle 
     E.14 E.14 Etched virgin Teflon 
     E.15 #1782 Stardust Quarry Finish Formica 
     E.16 #4552-50 Ebony Star countertop laminate 
     E.17 Glassboard (bead board or fiberglass reinforced panel) 
     E.18 Self-tapping threaded wood inserts 
     E.19 Cam levers 
     E.20 12-Volt cooling fans 
     E.21 Ladders (for big telescopes) 
     E.22 Small parts 
     E.23 Epoxy resins 
     E.24 Loading ramps, pneumatic wheels for wheelbarrow handles, and marine trailer jacks 
     E.25 Black aperture f/ratio labels 
     E.26 Plastic grommets for light shroud 
     E.27 Duct tape 
     E.28 Collimation tools 
     E.29 Commercial Components for Telescope Making 
                  E.29.1 Optics, focusers, digital setting circles, eyepieces, Telrads 
                  E.29.2 Spiders and secondary mirror holders 
                  E.29.3 Cast aluminum poles seat, clamping wedges, side bearings 
     E.51 Mirror Making Supplies 
                  E.51.1 Pyrex glass 
                  E.51.2 Kerr dental plaster 
                  E.51.3 MicroGrit abrasives 
                  E.51.4 Optical pitch 
                  E.51.5 Ronchi screens for mirror testing 

Customer reviews

Be the first to Write a Review for this item!


Please fill in the form below to ask a question.

Please add the two numbers