A telescope uses two convex lenses, an objective lens with a long focal length and an eyepiece with a short focal length. The objective lens converges parallel rays from a distant object to form a real, inverted image at its focal point. The eyepiece acts as a magnifying glass to create a virtual, upright and magnified final image at infinity for viewing. The telescope produces magnification through the objective lens forming an intermediate image that is further magnified by the eyepiece.

1. telescope

2. F o , F e F e Objective lens eyepiece I 1 I 2 , final image at infinity virtual , inverted ,magnified I 1 , real inverted, diminished

3. Made up of 2 convex lens : objective lens and eyepiece objective lens has a longer focal length Eyepiece has a short focal length

4. objective lens converges the parallel rays from a distant object and forms a real, inverted and diminshed image, I 0 at its focal point, F 0 Eyepiece lens is used as a magnifying glass to produce a virtual , upright and magnified image at I e

5. When the telescope is used in normal adjustment, the final image is produced at infinity This is done by adjusting the position of the eyepiece so that the real image , I 0 becomes the object at the focal point, F e of the eye piece

6. m = m o x m e Objective lens more powerful Eyepiece lens more powerful f o < f e f o > f e microscope Telescope