A refracting telescope is 45.0 cm long and the caption states that the telescope magnifies image

step 1 we have better than L equals 45 cm which equals some of the focal length of the objective and th

A refracting telescope is 45.0 cm long and the caption...

A refracting telescope is $45.0 \mathrm{cm}$ long and the caption states that the telescope magnifies images by a factor of $30.0 .$ Assuming these numbers are for viewing an object an infinite distance away with minimum eyestrain, what is the focal length of each of the two lenses?

Key Concepts

Refracting Telescope

A refracting telescope uses lenses to gather and focus light. It typically consists of two main lenses—the objective, which collects light from distant objects, and the eyepiece, which magnifies the image formed by the objective. This design is especially useful for astronomical observations where the object is effectively at an infinite distance.

Objective and Eyepiece Lenses

In a refracting telescope, the objective lens has a long focal length and is responsible for gathering light and forming a real, inverted image. The eyepiece lens, with a shorter focal length, takes this image and produces a magnified virtual image that the viewer observes. The performance of the telescope is heavily dependent on the proper pairing of these two lenses.

Angular Magnification

Angular magnification is the factor by which the telescope enlarges the angle under which a distant object is seen. In astronomical telescopes designed for viewing objects at infinity, the angular magnification is determined by the ratio of the focal length of the objective to that of the eyepiece. This concept is central to understanding how the telescope’s design parameters affect the apparent size of observed objects.

Focal Length

The focal length of a lens is the distance over which parallel rays of light are brought to a focus. In telescope design, the focal lengths of both the objective and the eyepiece directly influence the overall length of the telescope and its magnifying ability. Specifically, the telescope’s tube length for viewing distant objects is approximately the sum of the focal lengths of the objective and eyepiece lenses.

Please give Ace some feedback