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Telescope Jargon
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.
See Also:
Space-Travel.com News
About Telescopes
The Zodiac
The zodiac is a cycle that covers a year's time. There are several versions of the zodiac system. There is a Babylonian zodiac, an Indian zodiac, a Chinese zodiac, a Western zodiac, and several others. All of the various zodiacs are basically the same. They are all based upon the constellations and they all contain 12 stations, or signs.
The Western zodiac is the one that is mostly used in the United States. Modern Western astrological signs are really just simplifications of the signs used in Hellenistic times.
In the list below are the Roman names for the signs of the zodiac, their ecliptic longitudes of their first points, the symbols that represent them, and the associated dates:
Aries: 0°, the Ram, March 21 to April 20
Taurus: 30°, the Bull, April 20 to May 21
Gemini: 60°, the Twins, May 21 to June 21
Cancer: 90°, the Crab, June 22 to July 22
Leo: 120°, the Lion, July 23 to August 22
Virgo: 150°, the Virgin, August 23 to September 22
Libra: 180°, the Scales, September 23 to October 23
Scorpio: 210°, the Scorpion, October 24 to November 22
Sagittarius: 240°, the Archer, November 22 to December 21
Capricorn: 270°, the Sea-goat, December 22 to January 19
Aquarius: 300°, the Water Carrier, January 20 to February 18
Pisces: 330°, the Fish, February 19 to March 20
Sidereal zodiac astrology (used mostly by Indian astrologists) dates are different from the tropical zodiac astrology dates. However, the tropical zodiac dates are the ones that are used primarily in the West.
Astrology is not an exact science (if you think of it as a science). All of the implications of certain signs and the position of certain planets are open to interpretation. Different astrologists will give different readings based upon the same information.
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More articles:
Telescopes.com: Shop Telescopes and Telescope Eyepieces
AAS — Careers in Astronomy Brochure
Galileo Galilei - Wikipedia, the free encyclopedia
Solar System - Wikipedia, the free encyclopedia
AAS — Careers in Astronomy Brochure
The Constellations
NASA
In 1958, the Congress of the United States enacted, and the President Dwight D. Eisenhower signed, the National Aeronautics and Space Administration Act (NASA). The act begins with a very simple statement; "An Act to provide for research into the problems of flight within and outside the Earth's atmosphere, and for other purposes."
The Cold War between the United States and (what was) the Soviet Union was in full swing. With the passing and signing of the act that established NASA, what has come to be known as the "space race" was kicked off. The Soviet Union had launched Sputnik 1 and had an apparent head start in the race to space.
The United States caught up quickly. In January 1958, Explorer 1 (America's first earth satellite) was launched.
Then NASA launched human space flight initiatives with Mercury's single astronaut program (flights during 1961-1963) to determine if a human could survive in space.
The Project Gemini (flights during 1965-1966) with two astronauts to was used to practice space operations, like rendezvousing and docking spacecraft and extravehicular activity (EVA or space walks).
This was followed with Project Apollo (flights during 1968-1972) to explore the Moon. Since then NASA has conducted robotic missions to the Moon (Ranger, Surveyor, and Lunar Orbiter); Venus (Pioneer Venus), Mars (Mariner 4, Viking 1 and 2), and the outer planets (Pioneer 10 and 11, Voyager 1 and 2).
NASA has had its problems over the years. The space shuttle Challenger blew up on January 28, 1986, killing seven astronauts. The space program was grounded for two years. Another tragedy happened on February 1, 2003, when the space shuttle Columbia disintegrated on re-entry. All seven people on board were killed instantly.
Space travel is not without its dangers, but space in the next great frontier for mankind to conquer. You can be sure that the space program and NASA will continue into the foreseeable future.
Related Topics: Amateur Astronomy,
Astronomy for Kids, The Hubble Space Telescope
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