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Careers in Astronomy
Telescope Jargon
There is a language of astronomy. You need to know what the terms mean before you buy a telescope to ensure that you buy the telescope that is best suited for your needs. Some of the terms you will hear are:
1. Magnification and aperture: On the box that a telescope comes in, these two terms are represented by numbers like 6 x 30 or 8 x
50.
a. The first number represents the magnification. The number 6 means that distant objects appear to be 6 times their size when viewed through the telescope. Magnification is not as important, however, as aperture.
b. Aperture is represented by the second number and tells you the surface area of the lens or mirror of the telescope. The primary function of a telescope is to gather light. Aperture is more important than magnification in viewing celestial objects.
2. Focal length: Focal length is the distance that light travels from the telescope's lens or mirror to the focal point inside the telescope. The size of the image at the focal point will be larger the longer the focal point is.
3. Focal ratio: The term "focal ratio" is the ratio between the aperture and the focal length.
4. Refractor telescope: The refractor telescope gathers light through the use of a lens. Refraction is one of three ways in which telescopes gather light.
5. Reflector telescope: A reflector telescope gathers light through the use of a mirror.
6. Catadioptic telescope: A catadioptic telescope gathers light through the use of both lenses and mirrors.
7. Equatorial mount: An equatorial mount is a telescope mount with one axis that is parallel to the earth's axis, and points to the celestial North Pole.
8. Altazimuth Mount: An altazimuth mount is a telescope mount with two axes. It allows for movement in two directions, horizontally and vertically.
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The Planet Saturn
The planet Saturn resembles the planet Jupiter in many ways. Saturn is also a planet that has very little if any solid matter. It is believed that there is a hard rocky core, but that belief is unproven (albeit very probable) theory. Saturn, like Jupiter, is made up of gases and liquids. There is an internal heat source. We know this because Saturn radiates more energy than it receives.
Saturn rotates fast. It makes one complete revolution once every 10 or 11 hours. Saturn rotates around the sun once every 29.5 years. Because it rotates so fast, Saturn is flattened at the poles, making it an almost oblate planet.
The space probes, Pioneer 11, Mariner 11 and 12, and Voyager I and II, provide the best and most accurate information to astronomers about the planet Saturn, even though the Hubble space telescope takes very good images of Saturn. The space probes get "up close and personal," so to speak, and have provided information about Saturn that nothing else could have provided.
Wind velocity on Saturn is extreme. Wind speeds of more than 1,118 mph have been recorded. Unlike the winds on Jupiter, however, wind speeds on Saturn do not seem to be closely related to the positions of the belts and bands.
The rings around Saturn are one of the most interesting features. Really high-resolution pictures taken on the Voyager missions tell us that the rings are actually made up of hundreds of thousands of very small rings. The evidence suggests that the rings are composed of particles that are mostly ice crystals. A lot has been learned about the rings of Saturn over the last 20 or so years, but there is so much about them that is still a mystery. |
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Sir Christopher Wren
Sir Christopher Wren once said, "In things to be seen at once, much variety makes confusion, another vice of beauty. In things that are not seen at once, and have no respect one to another, great variety is commendable, provided this variety transgress not the rules of optics and
geometry." For those of you who do not know, Christopher Wren was an English architect and mathematician who became Savilian Professor of Astronomy at Oxford in 1661. He is most famous for the buildings that he designed after the Great Fire of London.
Wren was interested in many things, and over his lifetime, he made many contributions to scientific knowledge and in many different ways. For example, he constructed a transparent beehive for the purpose of scientific observation; he studied the moon and experimented on terrestrial magnetism; and he also performed the first successful injection of a substance into a dog's bloodstream.
Along with Sir Paul Neile, Wren constructed a 35-foot telescope. During this timeframe, Wren also studied and improved the microscope and the telescope.
Wren was fascinated by the planet, Saturn. He began his observations of Saturn about 1652 with the intention of explaining the rings. Wren developed a hypothesis which he wrote in De Corpore Saturni. Before his work could be published however, Christian Huygens (a Dutch astronomer) presented his theory of the rings of Saturn. Wren immediately recognized the fact that Huygens' was a better hypothesis than his own, so De Corpore Saturni was never published.
Wren constructed a beautifully detailed model of the moon and gave it to the king. Although Sir Christopher Wren eventually turned his attention to architecture, he remained fascinated by astronomy all of his life.
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