1. Scopes

2. Microscope  A microscope is a compound lens system designed to create high magnification. The intermediate image is magnifiedThe intermediate image is magnified Real imageReal image  The rays emerge parallel after the eyepiece. Acts like magnifying glassActs like magnifying glass objective intermediate image eyepiece

3. Objective  Microscopes try to maximize objective magnification. Large image distanceLarge image distance Use focal length nearly at object distanceUse focal length nearly at object distance Tube length LTube length L  The object is close to the objective. Small focal lengthSmall focal length Object just beyondObject just beyond

4. High Magnification  The eyepiece magnifies the intermediate image. Near point distance d n Take near point to be 25 cm Short focal length f E  Total magnification is the product. From x15 to x1200 Image is virtual

5. Refracting Telescope  A refracting telescope is designed to magnify a distant object. Object light rays nearly parallelObject light rays nearly parallel Final image rays also parallelFinal image rays also parallel primaryfocal pointeyepiece

6. Tube Length  The telescope intermediate image must be real. Distant objects very large Minimize intermediate to fit in tube Long focal length Long tube  The eyepiece then magnifies the intermediate image. Short focal length

7. Reflecting Telescope  A reflecting telescope combines a focusing mirror and a lens.  A single curved mirror and lens is a Newtonian reflector  An initial lens before the mirror is a Schmidt-Cassegrain primary mirror secondary diagonal mirror eyepiece

8. Aberration  A spherical lens does not exactly focus all parallel ray to a point. Thin lens is approximateThin lens is approximate  Real lenses have blurred edges called aberration. Spherical aberration from spherical lensesSpherical aberration from spherical lenses Chromatic aberration from different wavelength bendingChromatic aberration from different wavelength bending