Yi Zhang yqz5135

Caijia Liu cvl5213

Jiayu Fang jqf5138

While it is the human nature to explore the mystery of macrocosm and microcosm, this is limited by the lack of appropriate tools in the early time. The invention of telescope and microscope offered an opportunity for people to know better about the world.

Let’s start from convex lens and concave lens

History:1608: the earliest telescope appeared in NetherlandsIn 1668 Isaac Newtown build the the first reflecting

telescope. In 1733 Chester Moore Hall made achromatic lensIn 1931 radio telescope (along with radio astronomy)

was born with Karl Guthe Jansky's discovery of an astronomical radio source

There are a lot of types of telescopes, but the most common ones are Keplerin telescope and Galieo’s telescope.

Principles of telescopesKeplerian telescopeThe combination of an objective lens 1 and

some type of eyepiece 2 is used to gather more light than the human eye could collect on its own, focus it 5, and present the viewer with a brighter, clearer, and magnified virtual image 6.

Galileo’s telescope

Galileo telescope uses a convergent (plano-convex or bi-convex) objective lens and a divergent (plano-concave or bi-concave) eyepiece lens. Galilean telescopes produce upright images.

Parallel rays of light from a distant object (y) would be brought to a focus in the focal plane of the objective lens (F' L1 / y’). However, the (diverging) eyepiece (L2) lens intercepts these rays and renders them parallel once more, but travelling at a larger angle (α2 > α1) to the optical axis. This leads to an increase in the apparent angular size.

The final image (y’’) is a virtual image, located at infinity and is the same way up as the object

MicroscopeThere are many

types of microscopes, the most common and first to be invented is the optical microscope which uses light to image the sample.

According to the different distance of the objects, the image formations of the lens are different.

Principles of microscopes

Specifically,1) When Do>2f,then the image will be inverted, real and smaller. f<Di<2f 2) While Do=2f, then the image will be inverted, real and same size as the object. 3) While f<Do<2f, then the image will be inverted, real and larger, Di>2f. 4) While Do=f, then the image cannot be formed. 5) While Do<f, then the image will be erected, virtual and larger on the object side, Di>Do.

The distance of object in the microscope is larger than twice of the focal length, but smaller than one focal length of the tube lens, thus, the image will be inverted, real and larger. The image is then be magnified by the lens of eyes, so that eyes are able to see the image. The function of the lens of eyes is the same as the tube lens, the difference is that what the eyes see is not the real object, but the image that magnified by the tube lens.

Effects on people’s livesTelescopes have changed

the way man views himself in relation to the Universe. It is responsible for many important discoveries like determining the orbits of the planets in our solar system. The Hubble telescope shows us billions of galaxies, with billions of stars in each one. We can see the birth and death of stars, so we know what will happen to our own star in a few billion years.

We could never reach out as far as we have in the Universe without our telescopes.

Microscope provides us with chances to discover the microscopic world. Microscopes improve our lives by allowing scientists to study the smallest forms of life. These lifeforms include disease causing pathogens such as bacteria. The inventon of microscope has played an important role in the Medical Field.

References: http://www.google.com.hk/images?hl=zh-

cn&newwindow=1&safe=strict&client=aff-cs-360se channel&channel=bookmark&q=microscope%20change%20people's

%20lives&um=1&ie=UTF-8&source=og&sa=N&tab=wi&biw=1349&bih=580

http://en.wikipedia.org/wiki/Telescope http://en.wikipedia.org/wiki/Refracting_telescope http://www.google.com.hk/images?hl=zh-

cn&newwindow=1&safe=strict&client=aff-cs-360se-channel&channel=bookmark&q=telescope&um=1&ie=UTF-8&source=og&sa=N&tab=wi&biw=1349&bih=580

http://en.wikipedia.org/wiki/Microscope http://telescope.kingyar.com/?tag=%E6%9C%9B%E8%BF%9C

%E9%95%9C%E5%8E%86%E5%8F%B2 http://www.bjhwx.cn/xsxwj006.htm http://scholar.google.com/