http://gen.lib.rus.ec/search.php?&req=amateur+telescope+making
the classic manual series for DIY telescopes by Russell W. Porter und Albert Graham Ingalls, about lense- and mirror-making, coating and foucault-testing
http://gen.lib.rus.ec/search.php?&req=amateur+telescope+making
the classic manual series for DIY telescopes by Russell W. Porter und Albert Graham Ingalls, about lense- and mirror-making, coating and foucault-testing