Telescope

In today's lesson I have learnt about light and different types of telescopes.

1. Light

Reflection: Using mirrors bounce off smooth object and angle of incidence = angle to refraction.

Refractions : Bending of light via a medium

Light travels slower in a medium that is denser than the outside for like air and glass.

Light travels slower in glass than it does in the air so it would distort from its original path of light.

Light waves are usually transverse and they are also EM waves.

Huygens Fresnel principle states that every point of a wavefront is a source of wavelets they spread out in the forward direction at the same speed of the source waves. The new wavefront is a line tangent to all of the wavelets.

Surface reflection.

Flat surfaces reflect and bounce in the same direction and angle of the light.

Not flat surfaces means that the light rays would bounce off unevenly and the angles of reflections and incidence would not be the same

Light must always travel in straight lines. The particles will cast a shadow if not blocked.

2. Converging lens

When light passes through a medium, it converges to the focal point

If light passes through the optical center, it will remain in a straight line.

All of the light rays passing through the medium converge at the same focal point.

3. Applications to real life. Some possibilities.

Combination of both lenses. .

Eyepiece to eye

Objective to eyepiece

Types of telescope:

Reflector: Mirror to gather and focus light. Light rays coming are parallel.

Parabolic shaped focus lights to the single point

Advantages

1. Do not suffer from Chromatic aberration

2. Cheaper to make.

3. The size and the design of the open tube assembly mirror must be cleaned periodically.

4. WHen it is cleaned, realigning is expensive.

Refractor telescopes

1. Superior revolving

2. Inferior conditions

3. Minimal maintenance

4. Very high cost

5. Long term cost is cheaper

6. Chromatic aberration is unavoidable

In conclusion, I have learnt quite a bit about light and extend some of my learning as I learnt a little bit about light before. I have learnt how light or lenses peinciples can be applied into telescopes.I have also learnt about the different types of telescopes. Although we stopped halfway, I cannpt wait to see more about telescopes. I like how this lesson there are a lot of diagrams that were drawn such that students are able to visualise about the light diagrams, telescopes diagrams etc.