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Binoculars for 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.
See Also:
Re: harvesting and planting with the moon signs/phases
Nicolaus Copernicus
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:
Carl Sagan - Wikipedia, the free encyclopedia
Zodiac - Wikipedia, the free encyclopedia
Astronomy Clubs world wide
February 21 in Russian history. Amateur astronomy.
New Astronomy Video
Our Solar System
Our Solar System
Our solar system consists of our sun, eight planets, the 166 known moons that orbit these eight planets, 3 dwarf planets and the four known moons that orbit them. Our solar system also includes billions of other small bodies such as asteroids, Kuiper belt objects, comets, meteoroids, and interplanetary dust.
In short, our solar system is made up of our sun and all the celestial objects that are gravitationally bound to it.
The general outline of our solar system is (from the center outward):
1. The sun
2. Four terrestrial inner planets (Mercury, Venus, Earth, and Mars)
3. An asteroid belt (made up of rocky objects)
4. Four outer planets (Jupiter, Saturn, Neptune, and Uranus)
5. The Kuiper belt (made up of icy objects)
6. Scattered disc (poorly understood region)
7. Heliopause (where the sun's solar wind is stopped by the interstellar medium)
8. And finally, a hypothetical Oort Cloud (there is a lot of ongoing debate about the Oort Cloud).
Yes, there was another planet called Pluto, but it is no longer considered a planet. Back in August 2006, the International Astronomical Union (IAU) in Prague decided that Pluto did not meet the requirements to be designated a planet, and it is now classified as one of many dwarf planets.
In the dim and dusty past, it was believed that the Earth was the center of the universe and that everything else revolved around it, including the sun. That theory changed as knowledge was gained. The telescope was invented, and men could see farther and farther.
The formation of our solar system remains a basis of contention between some religious leaders and some scientists. There are some of each who believe that God created the universe in six days, just the way creation is described in the book of Genesis in the Bible. There are others who subscribe to the "Big Bang" theory. The debate has been raging for decades and shows no signs of abating. But however our solar system came into being, it is magnificent!
Related Topics: Galaxies,
Solar Eclipses, Astronomy Funny Bone
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