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Mirrors and Lenses
Test Your Astronomy Knowledge
So you think you know a lot about astronomy? Take this little test and find out. Do not scroll down to the answers until you have answered all five questions.
Question #1: One of the following is NOT a type of telescope. Which one?
A. Herschelian
B. Copernican
C. Gregorian
D. Newtonian
Question #2: What would be the magnification of a refractor telescope if the main objective lens had a focal length of 1200mm and the eyepiece had a focal length of 30mm?
A. 36x
B. 400x
C. 360x
D. 40x
Question #3: Only one of the following is a type of eye piece design. Which one?
A. Monocentric
B. Planocentric
C. Egocentric
D. Orthocentric
Question #4: You cannot see the Aurora Borealis in the Southern Hemisphere. True or False?
Question #5: If you are going to take extended exposure photographs of the sky, which mount is the best one to use?
A. Transit
B. Altazimuth
C. Equatorial
D. Dobsonian
Test Answers:
Question #1: The correct answer is B, Copernican. Nicolaus Copernicus was an astronomer, but no telescope was named after him.
Question #2: The correct answer is D, 40x. You calculate the magnification of a telescope by dividing the focal length of the lens or mirror by the focal length of the eye piece.
Question #3: The correct answer is A, Monocentric. Three glass elements are cemented together to make a monocentric eye piece.
Question #4: The correct answer is true. The word "Borealis" means northern. In the southern hemisphere, Aurora Australis is visible.
Question #5: The correct answer is C, Equatorial. An equatorial has to be driven by only one axis to track stars as the earth rotates.
So how did you do on this little test? If you answered three of the five questions correctly, you beat the average. If you answered fewer than three questions correctly, perhaps you should either study or take up another hobby.
See Also:
Galileo Galilei - Wikipedia, the free encyclopedia
Guide to Buying a Telescope
The Planet Jupiter
The planet Jupiter is was named by the Romans after their god Jupiter, who was also sometimes called Jove. Jupiter is the largest planet in our solar system by far. It is more than twice as large as all of the other planets combined.
Jupiter might well have become a star when it was born, had it been larger. There is very little (if any) solid matter on Jupiter. If there is any at all, it is hidden deeply inside the planet. Jupiter is made up entirely (as far as we know now) of gases and liquids.
The very composition of Jupiter means that its parts do not rotate at the same speed, but rotation is fast. Jupiter makes one complete revolution in a little less than 10 hours. This very fast rotation plus the makeup of gases and liquids are what causes the bulge at the equator of Jupiter.
Jupiter has an internal heat source. We are sure of this because it actually emits more radiation than it gets from the sun.
There are four large moons and dozens of small moons that rotate around Jupiter, making it a kind of small solar system unto itself.
One of the more outstanding features about Jupiter is the never-ending hurricane called "The Giant Red Spot" in the southern hemisphere. This disturbance has been going on for the last 400 years that we know of. It never abates…probably because it never passes over land (there isn't any) like hurricanes on earth do.
An explanation for the color of the clouds on Jupiter still eludes astronomers. With the conditions that exist, clouds should be colorless, but they are anything but colorless, and they change color over time. We still have a lot to learn! |
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More articles:
Pluto demoted - no longer a Planet!
Deep Sky Observing
Solar System - Wikipedia, the free encyclopedia
The Planet Jupiter
famous medical
Our Sun
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: Astronomy Clubs,
Deep Sky Objects, Sir Christopher Wren
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