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Nicolaus Copernicus
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:
Short focal Length Lense and Deep Sky Objects?
Binoculars for Astronomy
The Planet Neptune
Adams and Leverrier predicted the existence of the planet Neptune back in 1845. Neptune is very difficult to observe from the earth because of (1) the distance, and (2) the earth's atmosphere. The closest and best look that we have had at Neptune was provided by the Voyager 2 flyby in 1989.
Neptune is the most distant planet from the sun. It was once believed that Pluto was a planet Pluto beyond Neptune, but astronomers have declared that Pluto is not a planet but one of many dwarf planets in our solar system.
Neptune has a diameter that is about four times larger than earths. Computer models suggest that Neptune has a rocky core that comprises about 15 earth masses at the center, but there is no confirmation of this theory. Neptune has a rotation period of about 16 hours. Neptune has an internal heat source, and it produces about 2.7 times more heat than it absorbs.
Strong winds, bright, high-altitude clouds, and two large dark spots attributed to long-lived giant storm systems were reveled by the 1989 Voyager flyby. Wind speeds are as high as 739 miles per hour. The larger of the two dark spots that Voyager reveals is called the "Great Dark Spot."
Neptune's rings were first detected from Earth in 1983, but no real study could be conducted at that time. It wasn't until the data supplied by the Voyager 2 flyby was available that any determination about the rings could be disseminated. There are two bright rings and two fainter rings. The rings rotate in the same direction as Neptune, and they are all close to the equator.
Triton and Nereid are the two large moons of Neptune and are visible from Earth. Voyager 2 discovered six more moons, and one of them is actually larger than Nereid; but it is difficult to see because it orbits so close to Neptune. |
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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.
Related Topics: The Planet Jupiter,
Our Sun, Famous Meteorites
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