# How do you calculate the magnification of a Galilean telescope?

## How do you calculate the magnification of a Galilean telescope?

A Galilean telescope has an objective lens with f1 = 20 cm and the eyepiece lens with f2 = -5 cm. The lenses are separated by 15 cm. Calculate the matrix for this system and find mθ. M11 = mθ = +4 is the angular magnification.

**What is the magnifying power of Galilean telescope?**

2.5

Magnification is the negative ratio of focal length of the objective lens and focal length of the eye-piece. The magnifying power of the given Galilean telescope is 2.5.

**Which lens is used in Galilean telescope?**

convex lens

A Galilean telescope is defined as having one convex lens and one concave lens. The concave lens serves as the ocular lens, or the eyepiece, while the convex lens serves as the objective.

### Why does a Galilean telescope have narrower field of view than a Keplerian telescope with the same size lenses?

The focal length of the objective is greater than the distance between the two lenses. This explains why the telescope is shorter in length than the Keplerian version. The first lens (the objective) will focus the object just beyond the focal point of the second lens (the eyepiece).

**What is the formula for magnification of a telescope?**

Answer. The angular magnification is equal to the ratio fo/fe. Thus we have M = (10 m)/(0.1 m) = 100. The larger the focal length of the primary mirror, the greater will be the angular magnification of the telescope.

**What are the two converging lenses in a telescope?**

Most refracting telescopes use two main lenses. The largest lens is called the objective lens, and the smaller lens used for viewing is called the eyepiece lens.

#### Why is the image with Keplerian better than with Galilean?

Galilean telescopes are small and lightweight due to their rather simple optical design. Keplerian telescopes are longer and heavier as they incorporate prisms to reorient what would otherwise be an upside down and inverted image.

**What are uses of convex lens in day to day life?**

ANSWER (1) Uses of convex lens are:1) Convex lens is used in microscopes and magnifying glasses to subject all the light to a specific point. 2) Convex lens is used as a camera lens in cameras as they focus light for a clean picture3) Convex lens is used in the correction of hypermetropia.

**What is the power of a convex lens of focal length 15 cm?**

therefore the power of the lens is 0.067.

## How is the magnification of a Galilean telescope calculated?

To calculate the magnification of a Galilean telescope, we divide the focal length of the objective by the focal length of the eyepiece. So, if the focal length of the objective is 200 cm and the focal length of the eyepiece is 10 cm, the magnification of the telescope would be 20.

**Which is the objective lens in a telescope?**

The concave lens serves as the ocular lens, or the eyepiece, while the convex lens serves as the objective. The lens are situated on either side of a tube such that the focal point of the ocular lens is the same as the focal point for the objective lens.

**What are the disadvantages of a Galilean telescope?**

Keplerian telescopes, in contrast, invert the image. What are the disadvantages of a Galilean telescope? The Galilean telescope’s biggest disadvantage is its small field of view. A Galilean telescope typically has a field of view of about 15-18 arc minutes.

### How are parallel rays rendered parallel in a Galilean telescope?

With the lenses placed 20 cm = fo+feapart, the parallel input rays are rendered parallel again by the eyepiece lens, giving an image at infinity. This shows one of the uses of Galilean telescopes.