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Message: <blockquote data-quote="Binastro" data-source="post: 3476585" data-attributes="member: 111403">Hi Chosun,Zeiss were producing machine aspherics in the 1930s using machines developed by others before them.But obviously Sony's machine is much more capable, although I wonder how it copes with wear and how do you test the finished optical surface?Astro testing on the stars only tests surface accuracy, alignment and aberrations.For contrast with binoculars one needs terrestrial testing for contrast and colour rendition.Planetary observations with large telescopes tests contrast well and also ones eyes. But planets are too small for binoculars.Faint contrast detail on Saturn always eluded my eyes, although others saw it well.Similarly, some see detail on Neptune and Uranus, others never.I never saw detail on Jupiter's moons, others do.Planetary testing is more severe than star testing.</blockquote>