Although telescopes are the first thought for sky gazers, binoculars may be the ideal choice. Being portable, they are more convenient and inexpenseve compared with telescopes. It's wiser to buy a cheap pair of binoculars instead of a cheap telescope. 7 X 35 binoculars are a good choice because the size is light and easy to hold. The number 7 stands for the magnification produced by the binocular eyepiece, and the other number stands for the aperature in millimeters.
There are three types of telescopes available for beginning astronomers.
Refractors are the most readily recognized type and consist of lenses at both ends of a tube. Whatever you do avoid the cheap models sold by department, nature/science and toy stores. They quote large magnifications, but their small apertures make them useless for astronomy. Remember a telescope's most important job is to collect light, not magnify a image. A normal terrestrial telescope has an extra lens to ensure the image is the right way up. However extra lenses cut down the amount of light reaching the eye. The one thing an astronomer wants to avoid is reducing light and therefore information. So the correcting lens is omitted and a true astronomical telescope gives an upside down (inverted) image. Lenses can create false rainbow tints around very bright objects like planets. This is called chromatic aberration and can be ignored or corrected by a filter. Refractors generally cost more per inch of aperture than other types of telescope, and those of more than 4-inch (100mm) aperture are rather long and cumbersome. However smaller good quality ones can make excellent beginner instruments.
The next type of telescope is called the reflector, and these are usually comfortable because of the eyepiece position. In this telescope, light reflects off mirrors as is travels down the telescope tube and through the eyepiece on the side. In order to be as useful as a refractor, the reflector must be larger in size. Although they don't create false rainbow images, the main mirror on a reflector often needs to be readjusted, and there are kits for this. A popular type of reflector is called a Dobsonian, and this is convenient because it has a mount instead of a tripod.
The final type of amateur telescope is the Schmidt-Cassegrain, and this uses lenses and mirrors to fold a light path back onto itself within a compacted tube. This telescope is usually less expensive than refractors, dearer than reflectors, and are easier to handle than both.
Telescope specifications may quote numbers.These have no affect on the image you see, but can affect the exposure needed if you get into astrophotography. It's best to avoid astrophotography to start with. Become familiar with the sky and your telescope first.
By joining a local astonomy club or checking a library, you can evaluate different types of instruments. Also, astronomy magazines have reviews as well as advertising for good telescopes.
Although you should buy the biggest aperture you can afford, don't get a large telescope if you will have to carry it a long way. A smaller telescope would be easier to set up and therefore more likely to be used. You will also be wasting your money on a large telescope if light pollution and atmospheric turbulence in your area are high, as you won't be getting the best from the instrument.
It's best to spend most of your money on a buying a large aperture instead of telescope accessories. Doubling the aperture number will calculate the maximal practical magnification: i.e., a 70mm aperture will have a maximum magnification of 140x. Do not buy an eyepiece that is stated to stretch magnification past maximum aperture value. Start simple with eyepiece choices, such as a Kellner, which is a good all around eyepiece. If you place a Barlow lens between an eyepiece and focuser, magnification can be tripled.
Along with finding celestial objects, telescopes also follow the movement of those objects. The instrument must be moved repeatedly to keep the object in focus, and different mounts and drives make this possible. Electronic drives will point a telescope in the right direction, but the sturdiness of the mount is the most important thing.
It's important to know that many textbook and telescope advertisement photos are long exposures and have been given false colors. Since the eye isn't sensitive enough, stars will always look like small points of light and color will not be seen in dim objects.
So, let's talk about what you will see with a beginner telescope. With just a 75mm refractor or 150mm reflector, you can see nebulae, galaxies, moon craters, Saturn's rings, and even some of Jupiter's moons. All of these are amazing objects to view as you learn about the night sky. - 16928
There are three types of telescopes available for beginning astronomers.
Refractors are the most readily recognized type and consist of lenses at both ends of a tube. Whatever you do avoid the cheap models sold by department, nature/science and toy stores. They quote large magnifications, but their small apertures make them useless for astronomy. Remember a telescope's most important job is to collect light, not magnify a image. A normal terrestrial telescope has an extra lens to ensure the image is the right way up. However extra lenses cut down the amount of light reaching the eye. The one thing an astronomer wants to avoid is reducing light and therefore information. So the correcting lens is omitted and a true astronomical telescope gives an upside down (inverted) image. Lenses can create false rainbow tints around very bright objects like planets. This is called chromatic aberration and can be ignored or corrected by a filter. Refractors generally cost more per inch of aperture than other types of telescope, and those of more than 4-inch (100mm) aperture are rather long and cumbersome. However smaller good quality ones can make excellent beginner instruments.
The next type of telescope is called the reflector, and these are usually comfortable because of the eyepiece position. In this telescope, light reflects off mirrors as is travels down the telescope tube and through the eyepiece on the side. In order to be as useful as a refractor, the reflector must be larger in size. Although they don't create false rainbow images, the main mirror on a reflector often needs to be readjusted, and there are kits for this. A popular type of reflector is called a Dobsonian, and this is convenient because it has a mount instead of a tripod.
The final type of amateur telescope is the Schmidt-Cassegrain, and this uses lenses and mirrors to fold a light path back onto itself within a compacted tube. This telescope is usually less expensive than refractors, dearer than reflectors, and are easier to handle than both.
Telescope specifications may quote numbers.These have no affect on the image you see, but can affect the exposure needed if you get into astrophotography. It's best to avoid astrophotography to start with. Become familiar with the sky and your telescope first.
By joining a local astonomy club or checking a library, you can evaluate different types of instruments. Also, astronomy magazines have reviews as well as advertising for good telescopes.
Although you should buy the biggest aperture you can afford, don't get a large telescope if you will have to carry it a long way. A smaller telescope would be easier to set up and therefore more likely to be used. You will also be wasting your money on a large telescope if light pollution and atmospheric turbulence in your area are high, as you won't be getting the best from the instrument.
It's best to spend most of your money on a buying a large aperture instead of telescope accessories. Doubling the aperture number will calculate the maximal practical magnification: i.e., a 70mm aperture will have a maximum magnification of 140x. Do not buy an eyepiece that is stated to stretch magnification past maximum aperture value. Start simple with eyepiece choices, such as a Kellner, which is a good all around eyepiece. If you place a Barlow lens between an eyepiece and focuser, magnification can be tripled.
Along with finding celestial objects, telescopes also follow the movement of those objects. The instrument must be moved repeatedly to keep the object in focus, and different mounts and drives make this possible. Electronic drives will point a telescope in the right direction, but the sturdiness of the mount is the most important thing.
It's important to know that many textbook and telescope advertisement photos are long exposures and have been given false colors. Since the eye isn't sensitive enough, stars will always look like small points of light and color will not be seen in dim objects.
So, let's talk about what you will see with a beginner telescope. With just a 75mm refractor or 150mm reflector, you can see nebulae, galaxies, moon craters, Saturn's rings, and even some of Jupiter's moons. All of these are amazing objects to view as you learn about the night sky. - 16928
About the Author:
Information and resources can be found on David Wildash's website about Telescopes , and you can read more about buying a telescope
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