Astronomical Telescope (Refractions type) :

It is also made up two convex lenses. The objective is however of bigger size and greater focal length as compare to the eye-piece. The object is far away, the incident beam of light is therefore a parallel beam; the intermediate image R'S' is in the focal plane of the objective. This image R'S' is also allowed to be just within the focal length distance of the eye-piece. The final image produced RS is of much greater size than the intermediate image.

Index

Light

16.1 Laws of Reflection at plane surfaces
16.2 Mirrors
16.3 Laws of Refraction at plane surfaces, Refractive Index and Critical Angle
16.4 Refraction at curved spherical surfaces and Lens maker’s formula
16.5 Lenses
16.6 Refraction in Prisms, Prism Formula
16.7 Dispersion of Light, Angular Dispersion and Dispersive Power
16.8 Optical Instruments and Magnifying Power

Chapter 17