done by: liau yuan wei (3a317) friday, october 16, 2015done by: liau yuan wei1
TRANSCRIPT
Done by: Liau Yuan Wei (3A317)
Friday, April 21, 2023 Done by: Liau Yuan Wei 1
Content
Refracting telescope Light microscope Spectacles Cameras Binoculars
Friday, April 21, 2023 Done by: Liau Yuan Wei 2
Friday, April 21, 2023 Done by: Liau Yuan Wei 3
Origin
Refractors were the earliest type of optical telescope.
It emerged in 1608 in Europe, and 3 people were credited
They were Zacharias Janssen, Hans Lippershey and Jacob Adriaanszoon.
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A picture of Zacharias Janssen.
A painting of Hans Lippershey.
Both images taken from:http://www.aps.org/publications/apsnews/200403/history.cfm
Origin cont.
Galileo Galilei learned about the discovery in Venice.
He created and modified it to a better version to see the moons & planets.
He presented his version to the public, which was pleased with it.
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Image taken from:http://perraj.wordpress.com/2009/05/
A Picture of Refracting Telescope
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Objective lens
EyepieceFocal point
Image
Eye
Image taken from: http://en.wikipedia.org/wiki/File:Kepschem.png
Description
1 and 2 are used to gather more light than the human eye, focus it on 5, and present the viewer with a brighter, clearer, and magnified virtual image.
The objective lens refracts light.This refraction causes parallel light rays to converge at a focal point.
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Because the image is formed by the bending of light, or refraction, these telescopes are called refracting telescopes
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This clearly show the difference between a reflecting & refracting telescope.
Image taken from: http://csep10.phys.utk.edu/astr162/lect/light/refracting.html
Image taken from: http://visual.merriam-webster.com/astronomy/astronomical-observation/refracting-telescope/refracting-telescope.php
A picture of parts of the telescope.
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Image taken from: http://www.antonine-education.co.uk/Physics_A2/options/Module_5A/Topic_1/topic_1_lenses_and__refracting_t.htm
A picture describing how light moves in a refracting telescope.
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Origin
Came from the discovery of lenses. In 1590, Zaccharias Janssen and his
son Hans, created the microscope while experimenting with lenses in a tube.
In 1609, Galileo, heard of it, and made a better instrument with a focusing device.
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Origin cont.
Anton van Leeuwenhoek taught himself new methods for polishing tiny lenses of great curvature which gave magnifications up to 270 diameters.
This led to the creation of microscope and his biological discoveries.
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Image taken from:http://www.newworldencyclopedia.org/entry/Anton_van_Leeuwenhoek
A picture of Refraction in Light Microscope
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Here, refraction occur.
Image taken from: http://homepages.gac.edu/~cellab/chpts/chpt1/figure1-3.html
Yet another picture showing refraction.
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Refraction occurs here.
A Complex Image of the Optical Path
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Description
The objective lens is a lens with a very short focal length.
This is brought very close to the specimen being examined so that the light from the specimen comes to a focus.
This creates an enlarged image of the subject.
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The image is formed by the bending of light, or refraction, at the point where light bends to meet each other to form the image using lens.
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Image taken from:http://crescentok.com/staff/jaskew/ISR/equip/equip4.htm
A picture showing the parts of a light microscope.
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Origin
There are many claims to whom it was first invented, but they generally agreed that it was from 1200-1499.
At 1500-1899, the first significant advance in frame design occurred with lenses fixed to a rigid bridge, allowing them to stay in place.
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A Simple Diagram of Spectacles
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Eye (Not shown)
SpectacleLens
Image here is clearer and sharper.
Description
When light shine into the eye, the spectacle lens refracts the light inwards to meet at the back of the eye, giving a clearer and sharper view.
Without it, users would see images blurred as the image do not meet at the back of the eye.
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The image is formed by the bending of light, or refraction, at the point where light bends to meet each other to form the image using lens on the spectacles.
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Origin
The first photograph was taken in 1814 by Nicéphore Niépce using a sliding wooden box camera in Paris.
Cameras were a development of the camera obscura, which uses a pinhole to project an image outside upside-down.
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Taken from: http://www.boxcameras.com/telepococam.html
A diagram of the camera lens
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Taken from: http://www.mir.com.my/rb/photography/hardwares/classics/nikonf3/f3a.htm
This shows the path of light in a camera. Notice the light refracts when it enters the camera.
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Taken from: http://en.wikipedia.org/wiki/Photographic_lens
Distinct reflections are visible from the surfaces of different lens elements.
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Description
When a ray of light passes from a less dense to a more dense medium , it slows down.
If it strikes the glass surface at an angle, it is also bent a little, and this is called refraction.
This makes it possible to design a curved piece of glass that will focus a parallel beam of light to a point.
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Description
A photographic lens is an optical lens used in cameras.
They can be thought of as modified pinhole lenses.
They are normally made of four bits of glass.
Chromatic aberration and spherical aberration occur in a one-piece lens.
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Origin Came from invention of telescope. Galileo got the idea of mounting two of
them together and adapted an earlier design to create a magnifying effect.
In the mid-1850s, Ignazio Porro patented a design using two prisms constructed in a Z shape for the image to be better magnified, but has depth.
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Taken from: http://micro.magnet.fsu.edu/optics/timeline/people/porro.html
A Diagram of Binoculars
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Light is refracted here.
Taken from: http://en.wikipedia.org/wiki/Binoculars
This shows the path of light in a binoculars. Notice light is refracted when it enters it through the lens.
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A typical Porro prism binoculars design.
Taken from: http://www.nightskyinfo.com/binoculars
This shows the optical path of light inside a binoculars.
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A typical roof-prism binoculars.
Description
When light enters it, it is refracted by the objective lens.
It then travels and gets total internally reflected by two prisms.
This enables the image to turn it upside down as when light from a distant object pass through a convex lens, they cross over.
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Description
This turns the upside-down image previously upright for the eye.
Light then travels to the eyepiece lens, again getting refracted into the eye.
The 2 lens help to magnify the image too.
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References
http://en.wikipedia.org/wiki/Refracting_telescope
http://telescope-for-u.blogspot.com/2007/03/history-and-invention-of-refracting.html
http://csep10.phys.utk.edu/astr162/lect/light/refracting.html
http://inventors.about.com/od/mstartinventions/a/microscope.htm
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References
http://en.wikipedia.org/wiki/Optical_Microscope
http://www.aaofoundation.org/what/heritage/exhibits/online/spectacles/
http://wiki.answers.com/Q/How_does_a_camera_lens_work
http://en.wikipedia.org/wiki/Binoculars http://www.4u-binoculars.com/how-
binoculars-work.html
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References
http://www.binocularsinformation.com/history-of-binoculars/
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