760mm dobsonian also from Mr. Sloboda, deltagraph 465mm f/3.2 ( zimmerald widefield ?) with ASA 0.95x wynn corrector reference books: written by Leonid Sikoruk and Navashin Mikhail Sergeevich М.С.Навашин , “Телескоп Астронома Любителя,” Астрономическая Библиотека amateur telescope makers in Russia astronet astroclub ua