REACHING FOR THE STARS

[Music] [Music] The lure of the Stars has always been [Music] irresistible to increase his knowledge of the heavens man turned to one of his oldest materials glass this is the story of the steps that have brought the Stars closer steps on a Stairway of glass [Music] actually our Story begins over 3,000 years ago back then the Watchers of the Skies imagined that they saw the shapes of men and animals in the clusters of the stars above them they made accurate maps of many constellations and measured the Year by their movements across the sky the ancient Egyptians began their year in August with the return of Sirius the dog star the pyramids were used to site its position in the sky Sirius always returned just before the Nile River flooded warning the people to open the flood gates over a thousand years ago the Chinese had developed elaborate devices to plot the paths of the sun moon and the stars but these instruments depended on man's uned eye and could not truly unlock the mysteries of the universe in 1600 a Dutch maker eyeglasses Hans slippers discovered that two lenses combined made things appear to be closer he called his invention a spy glass because it was used to search for distant objects such as enemy ships and soldiers in Italy Galileo heard of the new invention and built an approved telescope to study the heavens Galileo's first observations through the telescope show that the planets are worlds like our own the four brightest moons of Jupiter are still named in honor of Galileo who discovered them astronomy now began to make giant strides forward with the help of glass a German astronomer Johannes Kepler plotted the orbit of Mars around the Sun 270 years before the first First artificial satellite went into orbit Sir Isaac Newton used his gravity discoveries to plot a satellite orbit and worked out the force formula we use today escape velocity equals 5 m/s the tool that aided these first steps toward the space age was the refracting telescope the main parts are the objective lens and the eyepiece light travels through this lens and is focused to form a tiny image at the bottom of the tube The Observer magnifies this image with the eyepiece a telescope is essentially a light Gathering instrument the larger and more perfect the lens the more light it can gather and the further man can see refracting telescopes improved over the years a major step came in 1790 when a Swiss glass maker developed the first true Optical glass for over a 100 years all Optical Quality Glass glass was produced in the same slow costly manner the glass maker patiently stirred a pot of molten glass after cooling the Melt was broken into large chunks imperfections and Bubbles were then shift out and the remaining pieces were reheated and pressed into shape from 2,000 lb of glass came less than 200 lb of usable material today thanks to technical development at Corning Flawless Optical quality glass is mass produced in huge volumes the product of automatic equipment for eyeglasses telescopes cameras and scientific instruments man knew that to increase the reach of his vision he must increase the size of his light Gathering lens but increased size means increased lens weight a really long-distance refracting telescope would become a monstrous thing that would tend to collapse of its own weight a whole new Optical system was devised the light Gathering lens was replaced by a mirror mounted at the base of the tube where it could be easily supported light rays entering the open end of the tube are reflected into a small mirror where they are again reflected to the focal point of the magnifying eyepiece because of this action the new system is called a reflecting telescope now larger telescopes could be built to reach further into space in 1928 a maker of giant telescopes Dr George Ellery hail began to dream about a huge 200 in reflecting telescope making such an enormous light Gathering mirror presented a problem steel or ordinary glass will expand under heat Shifting the critical focal point of the mirror what hard rigid material could be used a material that would not alter its shape when the surrounding temperature changed the search for a suitable mirror material for the hail telescope ended at Corning with a decision to use a special low expansion borosilicate glass in 1934 two Crews of men poured 42,000 lb of molten glass in 6 hours to form the 200 in disc a glass that is first cousin to the Pyrex brand oven wear used in your home over the years the Corning glass makers cast many telescope mirror blanks made of similar boros silicate glass they devise this ribbed pattern to reduce the weight of the huge piece of glass while retaining the necessary rigidity in this new method the mold filled with chunks of glass is moved into a huge oven there the glass slowly melts filling the mold completely after the disc is cast it must be slowly cooled in a special oven this controlled cooling process may take several months this big ey an 84in disc made by Corning for the kit Peak National observatory near Tucson Arizona had to be Precision ground and Polished to an optical accuracy of 2 millionth of an inch the modern giant telescope such as the hail telescope with its 200 in Mirror a top Palomar Mountain is in reality a gigantic camera a man rides in a cage at the Prime Focus to catch star images on the photographic plates 1 million pounds of telescope and mounting is so delicately balanced that a 1110th horsepower motor will swing it to track a star the Giant Eye of Palomar has captured the faint light of fantastically distant Galaxy light that took over 2 billion years to reach the Earth through this telescope man has witnessed unfamiliar Beauty And The Lure of the [Music] unknown the further he can see the greater Mysteries he uncovers but man is Never Satisfied all Earthbound telescopes have a common problem the Earth's atmosphere diffuses and distorts his view of the Heavens to solve this problem scientists developed large high altitude balloons capable of lifting telescopes above the turbulent atmosphere which surrounds the Earth here was the location for more perfect viewing but the extreme temperature changes of high altitude flights brought new problems to telescope makers the these high altitude telescopes require a mirror material that has even less thermal expansion than the borosilicate glass used in the hail telescope once again the glass makers at Corning found a solution in a near zero expansion glass called fused silica from which they fabricated a blank for a 36-in telescope mirror a mirror that could be safely lifted to the edge of outer space the fused silicon mirror is the light Gathering eye of a remarkable telescope camera that can be controlled from the ground through an intricate closed circuit television system and precise automatic control equipment the giant balloons of the stratoscope projects can climb Beyond 90% of the Earth's [Music] atmosphere at this altitude the small Airborne telescope provides details of the stars with far greater Clarity than the 200 in telescope at Palomar one of the first projects for these remote controlled telescopes was to study the nearest star our own Sun Earthbound telescopes have revealed the sun's violent nature better details of the sun's surface would give man information about the way heat is transported outward from the depth of a star this photograph from Project stratoscope 1 covers an area on the sun 43,000 M by 31,000 mil the Earth is dwarfed in comparison man is succeeding in obtaining his closer look the building blocks for this Stairway To the Stars are the product of Glass Technology lightweight mirrors of fused silica have been developed for use in satellites and Airborne telescope systems an unusual sandwich construction will reduce by half the weight of mirrors space Optics glass components for electronic circuitry will relay new information back to [Music] Earth glass radar tubes will scan new worlds and plot man's navigation into space dense shielding glass will protect man against the dangerous radiation of atomic power drives and Earth's encircling belts of cosmic radiation heat reflecting glass will help maintain even temperatures under the direct rays of the sun glass or ceramic Shields will protect Communications equipment against the glowing heat of re-entry television tubes will transmit the story of man's conquest of space pressure [Music] main stage 4 3 2 1 1 2 3 4 [Music] 5 the glass makers of Corning help prepare for man's Venture into outer space with viewports and radar windows that withstand the penetrating cold beyond our atmosphere and survive the shock and consuming heat of re-entry No Ordinary glass would do for these windows of Discovery glass that served its apprenticeship on Earth is now aiding man on his journey to the [Music] Stars