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				To understand why we have seasons, we need to look at the relations ... The sun's rays are pretty close to parallel to each other when they reach the Earth, ...			 
				
					http://daphne.palomar.edu/jthorngren/tutorial.htm				
									
							 
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					SkyandTelescope.com's Free E-newsletters. Weekly Bulletin ... Sky & Telescope, Night Sky, and SkyandTelescope.com are registered trademarks of New ...				 
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					Galaxy Zoo is an online, large-scale astronomical survey that asks volunteers to help classify galaxies.				 
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					Turn your computer into a virtual telescope. Microsoft's WorldWide Telescope brings together imagery from the best ground and space-based telescopes for a seamless exploration of the universe. Also offers guided tours of the sky by astronomers and educators.				 
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					A browser-based virtual planetarium of stars and planets customizable by location (latitude and longitude) and time of day.				 
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					Managed by the California Institute of Technology, is NASA's lead center for robotic exploration of the solar system.				 
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					Manufacturer of astronomical telescopes, CCD imaging systems, telescope accessories, binoculars, and microscopes.				 
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					KidsAstronomy.com is a powerful astronomy websited designed to introduce children to the facinating ... KidsAstronomy.com, part of the KidsKnowIt Network, is the ...				 
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					Complete astonomy textbook for first-year college courses.				 
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