Scopes Microscope A microscope is a compound lens

Scopes

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

Objective ] Microscopes try to maximize objective magnification. • Large image distance • Use focal length nearly at object distance • Tube length L ] The object is close to the objective. • Small focal length • Object just beyond

High Magnification ] The eyepiece magnifies the intermediate image. • • • Near point distance dn Take near point to be 25 cm Short focal length f. E ] Total magnification is the product. • From x 15 to x 1200 • Image is virtual

Refracting Telescope ] A refracting telescope is designed to magnify a distant object. • Object light rays nearly parallel • Final image rays also parallel primary focal point eyepiece

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

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 secondary diagonal mirror primary mirror eyepiece

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