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A Plea for Reflectors, Being a Description of the New Astronomical ...
No preview available - 2016
achromatic achromatic telescopes Alt-azimuth stand angle bear a power bright star Celestial Objects cell centre circular coloured constructed crown glass declination circle diagonal mirror diagonal plane diagram difficult double discs distilled water Ditto divide double stars Draconis employed equal equatorial stand equatorially mounted eye-tube favourable feet focus field of view flexure glass mirrors HERSCHEL high powers hitherto inches aperture inches diameter instrument JOHN BROWNING LARGE ALT-AZIMUTH large aperture metallic mirrors methods of mounting micrometer minutes moon nearly nebulae night object glass observatory observer obtained open air ounces of Solution parabolic curve parabolising PENNSYLVANIA STATE UNIVERSITY perfect performance pitch plane mirror position prism R. A. Proctor rays reflecting telescopes reflector refractors removed ring Saturn screw motions seen side silver surface SILVERED GLASS SPECULA silvering fluid Slack's small screw speculum metal spherical curve Star Atlas steady stop T. W. Webb tangent screw telescopes of large temperature tube unmounted viewing the sun With's