A Brief HistoryWhile many people are under the impression that Galileo Galilei invented the telescope, that's not true at all. We're not exactly sure who the true inventor was, there was even some controversy at the time. However, today, the honor is usually ascribed to the man who first requested a patent for the device from the government of the Netherlands in 1608, Hans Lippershey.
While Hans Lippershey presented his device to the government for military use, it was Galileo who realized its potential as a tool for astronomy. Even before he had seen one, Galileo started building his own telescopes, increasing the power with each generation until he had a thirty power device. With this new tool, he found mountains and craters on the moon, discovered that the Milky Way was composed of stars, and discovered the four largest moons of Jupiter.
The telescope continued to improve over the years and remained one of the primary tools for astronomy. In the 17th century, Sir Isaac Newton improved on the design of the reflector to create the telescope which bears his name. During the 20th century, German astronomer Bernhard Schmidt placed his mark on the design of the catadioptric telescope as did Russian astronomer, and D. Maksutov and Dutch astronomer, A. Bouwers.
One of the most famous telescopes today is the Hubble Space Telescope. Named after American astronomer Edwin P. Hubble (1889–1953), who confirmed an "expanding" universe, which provided the foundation for the Big Bang theory, Hubble launched April 24, 1990 from space shuttle Discovery (STS-31). While its future is currently unclear, it has produced some incredible imagery.
Telescopes for Amateur AstronomersTelescopes come in three basic designs; Refractor, Reflector, and Catadioptric. A refractor uses two lenses, one to collect light and focus it as a sharp image, while the other magnifies the image for the viewer. A reflector gathers the light at the bottom of the scope by a concave mirror, called the Primary while the image is focused either by a photographic plate or another mirror. The catadoptric combines elements of refractors and reflectors. Refractor optics are more resistant to misalignment but are limited in size. Reflectors do not suffer from chromatic aberration, but are easily misaligned and require frequent cleaning. More details are available in our article, Telescopes.
There are are 6 things to know about telescopes before going shopping.
- Power - A good scope will not talk about its “Power.”
- Refractor/Reflector - Advantages and disadvantages to each type. (See our article, Telescope Astronomy Basics.)
- Aperture - Aperture size is the true key to the "power" of a telescope[/link.
- Focal Ratio – Know a telescope’s focal ratio.
- Mount – Necessary for steady viewing.
- Eyepieces – Power is not the object.
Here are the steps for buying a telescope[/link: