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Message: <blockquote data-quote="Binastro" data-source="post: 3654574" data-attributes="member: 111403">Hi etudiant. post 19.The pocket scopes are difficult to use if one is not an expert as the metal bits may need bending slightly to get best images.Also I think that they are very difficult to make as Horace routinely aspherised everything using actual star tests to refine the optics.I addition some of his triplet correctors seem impossible for mere mortals to make.I don't know if anyone could actually make a pocket scope like Horace's to his standards.They are like jewels. (He actually used gemstones to make world record microscope objectives).Someone made a 5.5 inch Maksutov type scope and it didn't work because the primary was very badly corrected.He took it to Horace who made a special triplet corrector so it worked well.The corrector got broken and after Horace had passed away nobody could make another. It was replaced by a doublet. It still isn't very good. I bought the scope but I shouldn't really have done so as it is not a good performer.</blockquote>