Factors to Consider When Buying A Telescope

When you first become interested in buying a telescope, it can be somewhat of a daunting task. What kind of telescope do you really need? There are so many different kinds to choose from and a very large price range too. What do you want your new telescope to do, and do you really need all of the bells and whistles available? You don't want to pay good money for a telescope that won't give you a satisfactory experience, but neither do you want to pay for features that are just not necessary for what you need.

Here are a number of tips to keep in mind when you are thinking of buying a telescope.

Type of Objective - There are basically 2 kinds of telescope objectives available for home use. These are:

1. Refractor telescopes - these telescopes use a series of lenses to focus light onto the eyepiece. These telescopes are very rugged because they are a closed system and there are no mirrors to adjust so there is virtually no maintenance involved. These models produce some of the sharpest images available, but can be much more expensive to get a really good one.

2. Reflector telescopes - these telescopes use a series of mirrors to focus light onto the eyepiece. These telescopes are usually much more economical, but they are an open tube, so dirt and dust can collect on the mirrors. The mirrors will also need to be periodically aligned as well. However, you can get the most for your money with one of these if you don't mind the maintenance.

Aperture Diameter - The telescope's main function is to gather light, therefore the diameter, or at least the proportion of the objective's aperture is very important. The telescope's light-gathering strength is proportional to the objective's surface area, so bigger is not necessarily better unless the proportions are correct. A good rule of thumb for aperture width is about 3 inches (8 cm) for Refractors, and 4 - 8 inches (10 - 20 cm) for Reflectors.

Eyepiece - One of the most important things to check out when buying a telescope is the eyepiece. If you can afford it, get an eyepiece that is adjustable so that you can adjust the magnification - or at least get a telescope that has interchangeable eyepieces. A good steady focuser is also very important as you don't want the telescope to shake while focusing.

Magnification - Most beginners think that the most important feature in a new telescope would be high magnification, but that is not always the case. If the telescope's light gathering ability is insufficient, all the magnification in the world won't help. A magnification of 40X to 60X per inch of aperture is usually sufficient. The ability of the scope to enlarge an image and keep it sharp mainly depends on the lenses used and the focal length of the telescope.

Mounting - Last but not least, consider how your telescope will be mounted. Will it be mounted rigidly or will it be a portable mount? Make sure whatever mount you get has a low center of gravity so it won't tip over, and that it is the right size for the telescope you get. Mounting it at the right height as to avoid back fatigue is also very important.

Buying a telescope can be very exciting and challenging. Really the most important thing to do is to do your due diligence and research before you buy. Looking at the stars and seeing our planets up close and personal is one of the most incredible experiences a person will have, so you want to make sure you do it right. These tips should point you in the right direction when you consider buying a telescope.

Refractor Telescopes For The Serious Backyard Astronomer

Refractor Telescopes and Their Benefits

Ever since Galileo first invented the refractor telescope in the early 1600's, human beings have had a thirst to see the stars and planets close up. The first refractor, consisting of a convex objective lens at the base of a tube and a convex eyepiece at the top was actually first introduced in 1608 but perfected by Galileo in 1611. When we look into the night sky with our naked eye, it is hard to believe that just a couple of lenses could allow us to see the features of Jupiter, or the rings of Saturn or the billowing clouds of distant nebula, but it's true. If you love gazing up at the stars then getting a telescope is an investment you can't do without. But which kind of telescope should you buy?

There are basically 2 kinds of telescopes - reflector telescopes and refractor telescopes. As their names suggest, the reflector uses mirrors to reflect incoming light back to the eyepiece, while refractor uses lenses to refract or bend the light towards the eyepiece. In the movies, when you see Captain Ahab of the Moby Dick whip out a tube to look into, this is what a refractor telescope looks like.

This kind of telescope is the most common type of telescope for the amateur astronomer, and they are very good telescopes, but like anything else you might consider buying, there are always pros and cons.

Advantages of Refractors

One of the best features of these telescopes is that there is virtually no maintenance involved because there are no mirrors to clean or keep aligned. Also, it is a closed system so no moisture or dirt can get into the tube. It is one of the most rugged telescope designs and is easily transported. Also this type of telescope is good for daytime viewing such as looking at scenery or for bird watching. These telescopes are also generally lighter and easier to handle per inch of aperture and therefore easier for children to use.

Disadvantages of Refractors

However, these telescopes are by far the most expensive telescopes per inch of aperture. Also, lenses inherently disperse light into colors which will distort the incoming image. This is called chromatic aberration. There are apochromatic lenses that can correct this problem, and with this correction, these telescopes will give a fantastic image, but the price goes up dramatically when these lenses are employed. After about 3 inches of aperture, the price goes up radically as well. All in all, refractor telescopes, while giving an excellent image, may be a bit pricey for the first time, or amateur astronomer.

If you are a serious astronomer, then there is little choice, you must have a refractor telescope with an apochromatic correcting lens. However, if you are just starting out and not sure how serious your backyard habit may become, you might want to consider a less expensive reflector telescope for starters at least.