دانلود کتاب Choosing and Using a Dobsonian Telescope

In the 1980’s, on the sidewalks of San Francisco, amateur astronomer John Dobson began showing throngs of people how to build and use large aperture scopes, often from scraps. The Dobsonian,‘Dobs,’ are now the best-selling large telescopes in the world. There are a great variety of different Dob styles, ranging from elaborate and decorative creations to simple mass market designs, and new models appear all the time. In this title, Neil English presents the ultimate guide to buying and using a commercial Dobsonian for recreational astronomy. He provides in-depth accounts of the various models (plus accessories) on the market – both economy and premium – together with describing the wealth of innovations that amateurs have made to their Dobs to optimize their performance in the field. Even after thirty years of innovation, the Dobsonian Revolution shows no signs of abating. Find out where the future lies for these large aperture ‘scopes and the exciting avenues John Dobson’s vision will take us down in the coming years.