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Fotothek df tg Optik Dioptrik Licht Brechung Messinstrument Quadrant Winkel. Scan Deutsche Fotothek dftg color MIKCenter Berlin GmbH Figur Wrzburg Frankfurt Main Vermessung der Brechung des Lichts mit Quadrant Papier Kupferstich cm Optik Dioptrik Licht Brechung Messinstrument Quadrant Winkel ppn Druck Deutsche Fotothek