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Astronomy Funny Bone
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:
For once the answer may really be in the stars.
Telescope Jargon
The Planet Uranus
William Herschel accidentally discovered the planet Uranus in 1781. Uranus had been seen many times before, but it had always been dismissed as a star.
Uranus is made up mostly of hydrogen and helium like Jupiter and Saturn, but it has higher concentrations of heavy elements. Our closest look at Uranus was given to us by Voyager 2 in 1986.
Uranus is one of the four "Giant Gas Planets" (the other three are Jupiter, Saturn, and Neptune). The rings around Uranus are made up of rock, rather than ice like those of Saturn. We do know that there are five large moons and at least 10 smaller moons. The rotational period of Uranus is a little over 17 hours, and its orbital period is 84 years.
Uranus appears to be a giant blue featureless ball. Voyager 2 got relatively close to Uranus and could not pick up any distinguishable features. It is believed that the upper atmosphere of Uranus has a high-level petrochemical haze that probably obscures features lower in the atmosphere. The blue color is caused by methane gas in the atmosphere. Methane gas absorbs red and orange light, which leaves more blue light.
Voyager 2 confirmed that Uranus has a magnetic field. The field is more than 50 times stronger than that of Earth and is tilted about 60 degrees.
The latest scientific data suggests that Uranus is surrounded by at least five rings. The brightest ring is called the Epsilon ring. Voyager 2 located two small shepherd moons for it, one just inside and one just outside. These two shepherd moons have been named Ophelia and Cordelia.
The most interesting moon that circles Uranus is Miranda. Miranda isn't very big, but it has some very interesting geological features. |
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More articles:
Hubble Finds 67 New Gravitationally Lensed Galaxies
The Antikythera Mechanism
Total Lunar Eclipse
Solar System Exploration: Planets: Our Solar System
Christopher Wren - Wikipedia, the free encyclopedia
Basic Astronomy Quiz
Our Sun
There is nothing remarkable about our sun in the scheme of things. It is very similar to millions of other stars (and our sun is a star) in the universe. You might even call our sun an "average" star.
The energy source for our sun is nuclear fusion. If the total energy output of the sun for just one second could be captured, it would provide the United States with enough energy at the current level of usage for nine million years.
There is a hard core at the center of the sun. The core is so dense and the sun is so large that energy released in the center of the sun takes 50 million years to reach the surface. That means that if the sun suddenly stopped producing any energy at all at the core today, it would be another 50 million years before we noticed it here on earth.
Our sun has been producing radiant and thermal energy for the last four or five billion years. There is enough hydrogen for it to continue producing energy for at least another hundred billion years. In about 10-20 billion years, the sun will begin to expand. It will engulf the closest planets (including Earth), and then it will be a giant red star. In another few billion years after that, our sun will become what is known as a dwarf star.
Most people think of the sun as this large (huge), constant featureless fireball in the sky. The large part is right, but the constant (or steady) and the featureless parts are all wrong. Sunspots are a feature of the sun that was first noted by Theophrastus about 325 BC. A moderate-size sunspot is about the size of Earth. Sunspots come and go over a period of days or weeks.
Related Topics: Mirrors and Lenses,
About Telescopes, Planting by the Moon
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