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.
If you are considering a telescope there are essentially three types available to the amateur astronomer.
The most readily recognized type of telescope is the refractor, which has two lenses at the ends of its tube. It is important to avoid department store cheap models, as these quote large magnifications while having useless small apertures. Telescopes are made to collect light, not magnify images. Normal terrestrial telescopes have extra lenses to keep an image right side up, but this extra lense is left out of astronomical telescopes because it reduces light. Without a filter on the lens, rainbow tints can be seen around bright objects like planets. This is called chromatic aberration. Refractors can cost more than other types of telescopes, but, being smaller, these make great instruments for beginners.
Next is the reflector telescope, and in this type, light travels down the tube and reflects off mirrors before leaving through an eyepiece. The reflector does not have chromatic abberation, and needs to be larger than a refractor in order to be as equally effective. Reflectors are the most comfortable telescope usually because of the eyepiece position, but the main mirror may need to be adjusted frequently. Luckily, there are kits to help with this problem. The most popular type of reflector is the Dobsonian, which has a mount close to the ground instead of a tripod, keeping you from kneeling and possessing an elastic neck to look upwards.
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.
Even though you should purchase the largest aperture you find, keep in mind you may not want a large telescope as you may have to carry it around. Smaller telescopes are easier to set up and use, and high pollution in your area can keep a large telescope from producing results to its full potential.
The best way to calculate the maximum practical magnification is to double the aperture number: i.e. a 60mm aperture shoudl yield a 120x magnification. You shouldn't waste time on buying telescope accessories, but should instead invest in the largest aperture you can find. However, don't be tempted to purchase an eyepiece that claims to stretch magnification beyond the calculated aperture value. Start off simple in terms of eyepieces. A Kellner eyepiece is a great general purpose piece, and if you place a Barlow lens between it and a focuser, magnification may 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 may be saddening to know that many textbook photos have false colors and are long exposures. The eye is not sensitive enough to see color in dim objects, and stars will always look like tiny light points.
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. - 16069
If you are considering a telescope there are essentially three types available to the amateur astronomer.
The most readily recognized type of telescope is the refractor, which has two lenses at the ends of its tube. It is important to avoid department store cheap models, as these quote large magnifications while having useless small apertures. Telescopes are made to collect light, not magnify images. Normal terrestrial telescopes have extra lenses to keep an image right side up, but this extra lense is left out of astronomical telescopes because it reduces light. Without a filter on the lens, rainbow tints can be seen around bright objects like planets. This is called chromatic aberration. Refractors can cost more than other types of telescopes, but, being smaller, these make great instruments for beginners.
Next is the reflector telescope, and in this type, light travels down the tube and reflects off mirrors before leaving through an eyepiece. The reflector does not have chromatic abberation, and needs to be larger than a refractor in order to be as equally effective. Reflectors are the most comfortable telescope usually because of the eyepiece position, but the main mirror may need to be adjusted frequently. Luckily, there are kits to help with this problem. The most popular type of reflector is the Dobsonian, which has a mount close to the ground instead of a tripod, keeping you from kneeling and possessing an elastic neck to look upwards.
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.
Even though you should purchase the largest aperture you find, keep in mind you may not want a large telescope as you may have to carry it around. Smaller telescopes are easier to set up and use, and high pollution in your area can keep a large telescope from producing results to its full potential.
The best way to calculate the maximum practical magnification is to double the aperture number: i.e. a 60mm aperture shoudl yield a 120x magnification. You shouldn't waste time on buying telescope accessories, but should instead invest in the largest aperture you can find. However, don't be tempted to purchase an eyepiece that claims to stretch magnification beyond the calculated aperture value. Start off simple in terms of eyepieces. A Kellner eyepiece is a great general purpose piece, and if you place a Barlow lens between it and a focuser, magnification may 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 may be saddening to know that many textbook photos have false colors and are long exposures. The eye is not sensitive enough to see color in dim objects, and stars will always look like tiny light points.
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. - 16069
About the Author:
David Wildash posts information and resources on his website about Telescopes , and you can read more about buying a telescope
