Glass; that is all they had.
The Hubble Space Telescope was first launched April 24, 1990 .
Typically glass or plastic. If you are interested in learning specifically about contact lenses, you should visit Guru4Eyes.com (www.Guru4Eyes.com/contactlenses.html)
You put your finger in your eye and gently slide off the lenses
The first record of the use of lenses to manipulate images was in Greek and Roman writings of around 1000 A.D. As for the origins of someone using lenses to magnify a minute object, it is unclear. Most scientific instruments have a clear place in the historical records when they were formed and who created them, not the microscope though. The definition of the microscope makes it difficult to determine when it was first created. Since there were lenses dating back to ancient societies, how do we say when those lenses were used to look at minute objects? It is practically impossible to say when a single lens was used in that fashion. Credit for the first compound microscope (multiple lenses) is generally given to Zacharias Jansen and John Lippershey of the Netherlands, in 1590. It is likely that the microscope was a result of work made on the telescope. The telescope had much more practical uses in that time, because it could be used for maritime navigation.This idea is supported by the account of one of the first compound microscopes, which was six feet long and had a one inch barrel with a lens at either end. After the compound microscope the next major development was in lenses. Half a century after the compound microscope, both Anthony van Leeuwenhoek and Robert Hooke realized that lenses with very short focal lengths was the key to more magnification. This meant the use of extremely double convex or spherical lenses. They also used lenses made of pure quartz, creating a more pure glass instead of the poor quality, greenish glass of the day. The problem of making lenses in this fashion was that it created chromatic aberration. This aberration is because different wavelengths of light are refracted different amounts, resulting in a smeared image instead of a clear one. In 1758 John Dollard patented an achromatic lens. Even with this new lens, it was not until 1930 when Lister was able to use it to alleviate the problem of chromatic aberration. Much of the interim time was spent on telescope technology. Another form of the microscope, first proposed by Isaac Newton in 1692, is the reflecting microscope. In this case the light would not pass through a lens, but would reflect off of a concave mirror. Since all light is reflected the same, there would be no problem with chromatic aberration. The first reflecting microscope was made by Barker in 1736. This model was developed directly from reflecting telescope designs. Reflecting microscopes are used today, but the transmission type are much more prevalent.
The first record of the use of lenses to manipulate images was in Greek and Roman writings of around 1000 A.D. As for the origins of someone using lenses to magnify a minute object, it is unclear. Most scientific instruments have a clear place in the historical records when they were formed and who created them, not the microscope though. The definition of the microscope makes it difficult to determine when it was first created. Since there were lenses dating back to ancient societies, how do we say when those lenses were used to look at minute objects? It is practically impossible to say when a single lens was used in that fashion. Credit for the first compound microscope (multiple lenses) is generally given to Zacharias Jansen and John Lippershey of the Netherlands, in 1590. It is likely that the microscope was a result of work made on the telescope. The telescope had much more practical uses in that time, because it could be used for maritime navigation.This idea is supported by the account of one of the first compound microscopes, which was six feet long and had a one inch barrel with a lens at either end. After the compound microscope the next major development was in lenses. Half a century after the compound microscope, both Anthony van Leeuwenhoek and Robert Hooke realized that lenses with very short focal lengths was the key to more magnification. This meant the use of extremely double convex or spherical lenses. They also used lenses made of pure quartz, creating a more pure glass instead of the poor quality, greenish glass of the day. The problem of making lenses in this fashion was that it created chromatic aberration. This aberration is because different wavelengths of light are refracted different amounts, resulting in a smeared image instead of a clear one. In 1758 John Dollard patented an achromatic lens. Even with this new lens, it was not until 1930 when Lister was able to use it to alleviate the problem of chromatic aberration. Much of the interim time was spent on telescope technology. Another form of the microscope, first proposed by Isaac newton in 1692, is the reflecting microscope. In this case the light would not pass through a lens, but would reflect off of a concave mirror. Since all light is reflected the same, there would be no problem with chromatic aberration. The first reflecting microscope was made by Barker in 1736. This model was developed directly from reflecting telescope designs. Reflecting microscopes are used today, but the transmission type are much more prevalent.
Phoenicians cooking on sand discovered glass around 3500 BC, but it took about 5,000 years more for glass to be shaped into a lens for the first telescope. A spectacle maker probably assembled the first telescope. Hans Lippershey (1570-1619) of Holland is often credited with the invention, but he almost certainly was not the first to make one. Lippershey was, however, the first to make the new device widely known.
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Telescopes, were essentially discovered in 1609. Galileo and later Keppler were the first astronomers to use them. They caught on rapidly as observing instruments and for look out purposes., it took the optician's a while to correct the inverted view on some of them, but once done, they took off.
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by cleaning the specs
A polarized lens cuts more reflected glare but the actual protection of polarized lenses and G15 lenses are the same. Polarized sunglass lenses reduce glare reflected off roads, bodies of water, snow, and other horizontal surfaces where the G15 lenses do not.
When they blow off you can spot them with a telescope.