Aim

To understand the construction and working of an astronomical telescope using convex lenses of suitable focal lengths.

Introduction

Apparatus used

Convex lenses of focal lengths 10 cm and 30 cm

Ivory sheets

Adhesive tape

Theory and working

1.)Construction

2.)Working of astronomical telescope

Magnification for the telescope made by two given lenses

fo = 30cm = 0.3mfe = 10cm = 0.1m D = 25cm = 0.25m

m = - 0.30.1 (1+ 0.10.25

) = -4.2 for image at least ditance of distinct vission

m = - 0.30.10.10.25 = -1.2 for image at infinity

Conclusion

The astronomical telescope designed is able to produce real, inverted and magnified images of the objects very far away from it.

Sources of errors

Write yourself

Precautions

Write yourself

Bibliography

NCERT textbook of class 12

Physics by S.L.Arora

Designs available on internet