A stargazer has an astronomical telescope with an objective whose focal length is 195 cm and an eyepiece whose focal length is 1.08 cm. He wants to increase the angular magnification of a galaxy under view by replacing the telescope's eyepiece. Once the eyepiece is replaced, the barrel of the telescope must be adjusted to bring the galaxy back into focus. If the barrel can only be shortened by 0.56 cm from its current length, what is the best angular magnification the stargazer will be able to achieve

The best angular magnification is

-375

Explanation:

Fe = Fo - L

From the question, (Fo) = 1.08 cm while (L) = 0.56cm

Thus, Fe = 1.08 - 0.56 = 0.52cm

Now, let's apply the angular magnification equation ;

M = - Di/Do

Where Di is the distance from the lens to the image and Do is the distance of the object to the lens.

In this question, Di is represented by f which is the distance from the lens to the image and it is f= 195cm

Also,Do is represented by Fe which is 0.52cm and it is the distance of the object to the lens.

Thus m = - f/fe = - 195/0.52 = - 375

. west