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.
Refractors consist of lenses at both ends, and the most recognized type of telescope. They generally cost more per aperture inch than other telescopes, but their size makes them ideal beginner telescopes. It's best to avoid cheap department store models, as these quote large magnifications but have small, useless apertures. The job of a telescope is to collect an images light, not magnify it, so large magnifications actually make things worse and can alter data. Earthly telescopes usually have extra lenses to make an image appear right side up, but this extra lense can cut down the amount of light that reaches the eye. Therefore, the extra lense is left out of astronomical telescopes, which leaves images upside down. Since lenses can create false rainbow images around really bright objects, it's best to buy a filter to help correct the problem.
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 third type of telescope is the Schmidt-Cassegrain. This uses lenses and mirrors to fold the light path back on itself within a compact tube. They are generally cheaper than refractors, but dearer than reflectors. They are more portable and easier to handle than the other two.
Sometimes telescope specifications quote numbers which will not affect the image you see. However, they can affect the exposure you need if you start into astrophotography. It is wise to get familiar with your telescope and the sky before you look into astrophotography though.
You may be able to evaluate the different instruments by joining a local astronomy club or attending one of their star parties. Check at your local library. You can also look in a reputable astronomy magazine for reviews and manufacturers advertising good quality telescopes.
Purchasing the largest aperture you can find is the best idea, but don't buy a telescope larger than you can lug around. Smaller telescopes are easier to set up and more convenient to use. You also don't want to waste your money on a large telescope if atmospheric pollution is high in your area, as this will prevent the telescope from giving you its best results.
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.
A telescope also magnifies the movement of objects across the sky and the instrument will have to be moved repeatedly to keep the object in the field of view. To cope with this different mounts and drives have been devised that enable the telescope to follow the moving object. You can get electronic drives to point the telescope, but the most important thing is that the mount is sturdy.
It is important to realize that many textbook and telescope advertisement photos are long exposures with false colors added. Stars seen through a telescope will always look like points of light, and you will not see color in dim objects. The eye is not sensitive enough.
Now, what will you be able to see with a novice telescope? With a 75mm refractor or 150mm reflector, you may see galaxies, nebulae, Saturn's rings, the large Jupiter moons, and countless craters on the moon. There are plenty celestial objects to help introduce you to the night sky.
If you are considering a telescope there are essentially three types available to the amateur astronomer.
Refractors consist of lenses at both ends, and the most recognized type of telescope. They generally cost more per aperture inch than other telescopes, but their size makes them ideal beginner telescopes. It's best to avoid cheap department store models, as these quote large magnifications but have small, useless apertures. The job of a telescope is to collect an images light, not magnify it, so large magnifications actually make things worse and can alter data. Earthly telescopes usually have extra lenses to make an image appear right side up, but this extra lense can cut down the amount of light that reaches the eye. Therefore, the extra lense is left out of astronomical telescopes, which leaves images upside down. Since lenses can create false rainbow images around really bright objects, it's best to buy a filter to help correct the problem.
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 third type of telescope is the Schmidt-Cassegrain. This uses lenses and mirrors to fold the light path back on itself within a compact tube. They are generally cheaper than refractors, but dearer than reflectors. They are more portable and easier to handle than the other two.
Sometimes telescope specifications quote numbers which will not affect the image you see. However, they can affect the exposure you need if you start into astrophotography. It is wise to get familiar with your telescope and the sky before you look into astrophotography though.
You may be able to evaluate the different instruments by joining a local astronomy club or attending one of their star parties. Check at your local library. You can also look in a reputable astronomy magazine for reviews and manufacturers advertising good quality telescopes.
Purchasing the largest aperture you can find is the best idea, but don't buy a telescope larger than you can lug around. Smaller telescopes are easier to set up and more convenient to use. You also don't want to waste your money on a large telescope if atmospheric pollution is high in your area, as this will prevent the telescope from giving you its best results.
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.
A telescope also magnifies the movement of objects across the sky and the instrument will have to be moved repeatedly to keep the object in the field of view. To cope with this different mounts and drives have been devised that enable the telescope to follow the moving object. You can get electronic drives to point the telescope, but the most important thing is that the mount is sturdy.
It is important to realize that many textbook and telescope advertisement photos are long exposures with false colors added. Stars seen through a telescope will always look like points of light, and you will not see color in dim objects. The eye is not sensitive enough.
Now, what will you be able to see with a novice telescope? With a 75mm refractor or 150mm reflector, you may see galaxies, nebulae, Saturn's rings, the large Jupiter moons, and countless craters on the moon. There are plenty celestial objects to help introduce you to the night sky.
About the Author:
David Wildash shares information and resources on his website about Telescopes , and you can read more about buying a telescope
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