Charles Packard

Ted Coskey

Astronomy 100

April 12, 2009

 

TELESCOPES

 

            Telescopes were invented in the begging toward the 15th century and now have evolved from terrestrial based to orbital satellites.  The first telescope was invented by Hans Lippershey (ca. 1570-1619) who was a German-Dutch glass maker and in 1608 was the first scientist to apply for a patent.  However in 1609 an Italian astronomer Galileo developed his own refracting telescope to look up at the stars.  That means that Christopher Columbus who was looking for the new world did not have a telescope to see from his ship.

            Telescopes for observing the stars and planets fall in to two kinds, refracting and reflecting.  Refracting telescopes where popular over a century ago where the image comes from a huge single primary lens but suffered optical distortions and the primary lens is very expensive to manufacture.  The refracting telescopes where popular up to the end of the 19th century when reflecting telescopes took there place.  The largest refracting telescope was completed in 1897 with the primary lens 1 meter in diameter at Yerkes Observatory in Wisconsin.   

            Reflecting telescopes require a primary mirror where the mirror is ground concaved to reflect the light to a single point where usually another mirror redirects the light to an eyepiece which can be magnified for the person looking.  Also, sagging and the problem with optical distortion are less using a reflecting telescope.  All very large telescopes are now reflecting instead of refractory when built big.  Like the other two telescopes that where built later at Yerkes Observatory with a primary mirror of 102 cm and 61 cm.  However, no matter how big your telescope you’re using on Earth there are problems with light pollution, and seeing through the atmosphere.

            19 years ago, the Space Shuttle Discovery and its crew prepared for the first telescope satellite, named after an American astronomer, the Hubble or HST.  The Hubble is a reflector based telescope with a 2.4 meter mirror and they had the first problem which after all the work to put it there in space, the primary mirror was ground incorrectly causing the images to look fuzzy.  The Hubble is like the size of a school bus and scientist involved came up with a plan to fix it in 1993.  There have been a total of four missions to the Hubble and might be a fifth mission this next coming month.  Also, the Hubble can detect much more detail then any terrestrial telescopes on Earth. 

            There has been two more exciting telescopes launched into orbit, like the Chandra ten years ago which examines X-Rays and six year ago the Spitzer which measures infrared which is almost impossible to detect on the ground.  Then the latest Space Telescope named James Webb is planned to be launched in June 2013 for observing infrared like the Spitzer Space Telescope. 

           

 

 

 

 

Sited

 

"Space - Who Invented The Telescope?." Science Fact Finder. Ed. Phillis Engelbert. UXL-Gale, 1998. eNotes.com. 2006. 13 Apr, 2009 http://www.enotes.com/science-fact-finder/
space/who-invented-telescope

 

“Yerkes Observatory” Wikipedia.org 14 Apr, 2009 http://en.wikipedia.org/wiki/Yerkes_Observatory

 

“James Webb Space Telescope” Wikipedia.org  14 Apr, 2009

http://en.wikipedia.org/wiki/James_Webb_Space_Telescope