دانلود کتاب The Dobsonian telescope : a practical manual for building large aperture telescopes

This book tells how you can build a state-of-the-art Dobsonian telescope using readily available materials and supplies. Every step of construction is detailedin 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 builtfrom 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 transp