Lesson: Telescopes

What is the angular magnification of a telescope that has a 100 cm-focal length objective and a 2.50 cm-focal length eyepiece?

A planet at a distance of m from Earth is observed by a telescope that has a focal length of the eyepiece of 1 cm and a focal length of the objective of 1 cm. The planet is seen to subtend an angle of rad at the eyepiece. What is the size of the planet?

Two stars that are km apart are viewed by a telescope and found to be separated by an angle of radians . If the eyepiece of the telescope has a focal length of 1.5 cm and the objective has a focal length of 3 meters, how far away are the stars from the observer?