The final image formed by an astronomical telescope is

$A$ simple telescope consisting of an objective of focal length $60\,cm$ and a single eye-lens of focal length $5\,cm$ is focused on a distant object in such a way that parallel rays emerge from the eye-lens. If the object makes an angle of $2^o$ at the objective,the angular width of the image is.....$^o$

An object is clearly seen through an astronomical telescope of length $50 \ cm$. The focal lengths of its objective and eyepiece,respectively,can be

$(a)$ $A$ small telescope has an objective lens of focal length $140\;cm$ and an eyepiece of focal length $5.0\;cm$. What is the separation between the objective lens and the eyepiece?
$(b)$ If this telescope is used to view a $100\;m$ tall tower $3\;km$ away,what is the height of the image of the tower formed by the objective lens?
$(c)$ What is the height of the final image of the tower if it is formed at $25\;cm$?

The large aperture of an astronomical telescope is used to:

If the focal lengths of the objective and eyepiece of an astronomical telescope are $200 \, cm$ and $4 \, cm$ respectively,what will be the magnifying power for distant vision (normal adjustment)?