They're often marketed as a simpler scope, great for a novice. These have computerized mounts that allow them to point all by themselves. So don't fall for the marketing claims of those cheap flimsy scopes with "400X" printed on the box.Ī popular type of scope these days are the "Go To" telescopes. So even for big backyard telescopes the practical magnifying limit is really around 250X on a good night, less on a not so steady and clear night. When magnifying celestial objects, you're also magnifying the blurring effects of the Earth's atmosphere. The backyard telescope is not just limited by the scope itself but also the sky conditions. But every time you double the magnification, the brightness drops by 4 times. A 6-inch scope may be able to go to 300 power. So for a 2-inch telescope, the maximum theoretical magnification is about 100 power. The maximum theoretical magnification can be estimated by multiplying the aperture (in inches) by 50. Theoretically any telescope can be set to any power, but practically speaking there is a limit before the image gets too dim and fuzzy.
A magnification of 50X is plenty of power to see the phases of Venus, rings of Saturn, moons of Jupiter and craters on the Moon.Īs shown in the formula below, a smaller eyepiece gives you a higher magnification. Switching to a high power magnification reduces brightness and sharpness. The magnification of a telescope is easily changed by changing the eyepiece. Magnification is not as important as most people think. Some of the biggest telescopes at major observatories are almost 400 inches in aperture. Typical reflectors are often around 6, 8 or 10 inches. Common store bought refractors can often be found in the 2 inch range. (The main lens or mirror is called the objective.) A bigger aperture gives you a brighter image. The aperture refers to the size of the telescope's main lens or mirror. Many homebuilt telescopes are of the Dobsonian design.Īperture is an important factor as well. Dobsonian telescopes are almost always Newtonian telescopes in a Dobsonian mount. It was invented in the 1960's by John Dobson. Too often people overlook the mount and end up with a telescope that shakes every time it's touched or every time the wind blows.Ī very popular type of telescope mount is the Dobsonian mount. A telescope needs a very sturdy and stable mount. When buying a telescope, a very important thing to consider is the mount. Their advantage is that they are shorter, therefore more portable, but still have a large aperture for gathering more light. The eyepiece is often in the bottom end like a refractor. Catadioptrics or "compound" telescopes tend to be short and fat. Reflecting telescopes are often called Newtonian telescopes.Ī catadioptric telescope uses mirrors and lenses. The eyepiece is usually on the side near the top rather than at the bottom. They tend to be fatter than refractors but just as long. They tend to be long and skinny.Ī reflecting telescope uses mirrors and was invented by Sir Isaac Newton. This was the type Galileo used 400 years ago. The refractor is the stereotypical telescope. Reflecting scopes use mirrors and catadioptric scopes use a combination of lenses and mirrors. First off, there are three basic types of telescopes: refracting, reflecting and catadioptric.
0 kommentar(er)
