Notre Dame extended Research Community 1 Optics and Visible Light Michael Crocker Valerie Goss Rebecca Quardokus 2 How do we see? target source detector and often youll need a lens 3 Magnifying Glass Magnification: 2-10x (Loupes 30x) One lens (Many Lenses and Prisms) Usually a biconvex lens - both sides are convex 4 Focal Length Magnified Right Side Up Shrunk Upside Side Up Focal Length 5 Chromatic Aberration A kind of distortion (color) Can be fixed to a certain extent Imperfections also lead to distortions Tilting the lens leads to another distortion 6 Examples of Chromatic Aberration 7 Activity: Assemble the Telescope! Arrrrgh! 8 Telescope #1 Galilean Telescope Produces Upright Images 9 Telescope #2 Wider Field of View 10 Telescope #3 Allows for Larger Objectives (collects more light) Reflecting Telescope 11 Microscope Light Source Stage and Sample Objective Lens Ocular Lens (Eyepiece) 12 Telescope -> Microscope 13 Magnification Objective Lenses 4x Magnification 10x Magnification 40x Magnification 100x Magnification 10x Magnification Total Magnification: 40x, 100x, 400x, 1000x Other techniques: Feature Size 14 Focus Coarse and Fine Focus Knobs Larger Magnification Usually Means Shorter Depth of Field 15 Example Image 16 Digital Microscope 17 Direct Viewing Light from the sample goes directly to your eye 18 Indirect Viewing Light from the sample goes to a sensor, and an image is produced later on film, a screen, or as data in a computer 19 Images and Rasterisation Computer Graphics: Any Magnification What about feature size? 20 Digital Microscope Time! Try looking at different objects Fill out lab sheet about magnification 21 Microscopy without Light Other radiation Special sensors Machine intervention Computer image processing False Color 22 Scale 23 X-Rays and Gamma-Rays! 24 Other Radiation Radio Waves 25 What Comes Next? How to view things that do not emit light? How to view things smaller than the wavelength of light? What do we actually see when we use such techniques?