Question

3. Think about refracting telescope system of below figure for all finite distance r. Make sure that you should consider all distance regime of r explicitly. And linear magnification is calculated as Mlinear(r) = - where s is object distance, and s' is the image distance. In this two-lens system, you can first get image of object for one lens and apply that image as an object of a second lens. The sign convention for each lens applies same as before, and the order of applying lenses does not matter. However, in this problem, please apply objective lens first and then apply eye piece lens for easier grading by TA. The total magnification is product of two lens magnification : Mtot = mobjective lens Meyepiece lens 100 Calculate linear magnification Mlinear(r) in terms of fe, fo,r, and show that lim Mzinear (r) = _fe. The magnitude of magnification (|m]) is the ratio of the size of the fo image to the size of the object. The () sign means the final image is inverted, where (+) sign means the final image is upright. You can find lim Mangular (Y) = -o in textbook. Thus, lim Mlinear(r)Mangular (r) = 1. If we consider our eye as a third lens with focal So feye fo2 length feye at the focal point of eyepiece lens, we can get Mlinear(r) = for r >> and Minear (r) & Anyway, this is the reason you should use angular magnification instead of linear magnification at eyes because it simplifies the magnification effect at eyes. If you use linear magnification, you should think your eyes as an additional lens. 1-00 fer object s from of object fo+fe IM' TU OB r eye image at infinity