How Do Telescopes Work - Telescope Lenses

Lenses and mirrors are the elements used to collect and view focused light in telescopes. Mirrors are the medium for focusing in reflector telescopes, while lenses are the medium in refractors. Each type has its own distinct advantages and disadvantages. Refractor type telescopes use lenses. These lenses bend the light when it enters the telescope from the distant object being viewed through it. Because of this refraction it is possible to closely view a distant object. The telescope has two lenses, with one slightly larger.
The eyepiece in the telescope is generally a small lens. Some telescope however, may not use lenses for the eyepiece at all. The eyepiece, in any case, is the most important element of a telescope. It is the element which lets you see correctly whatever it is that you want to focus on. These eyepieces are adjustable and are of a low power. Adjusting the eyepiece allows you to change the magnification factor. What kind of lens you use for the eyepiece is a personal choice. In today's age, several different kinds of eyepieces are available in the market. Because of this motley available, choosing the correct eyepiece fro your requirement may be a difficult task. As a result, you should concentrate on defining the criteria you think are important for your choice. The depth of field, optical quality, sharpness, clarity, brightness, market price, barrel size and how it affects your eyesight are some of the major points of concern. However these criteria always remain individual prerogatives.
Lens designs used in older telescopes go by the name of Huygens and Ramsden. Professional astronomers are advised to not use these lenses anymore as they are not of superior quality, even though they are comparatively less expensive than other market lenses. These lenses also do not provide correction for chromatic aberration or the light circles that form around brighter objects when they are viewed.
Professional astronomers use orthoscopic lenses that are designed specifically for professional stargazing. Even amateurs will find these lenses good for their telescopes. The orthoscopic telescopes use four lenses in the eyepiece, and have a 45 degree field of vision (FOV). Since the eyepiece is the element most important to the quality of a telescope, this design is a winner. The lenses do not strain the user's eyes, and can be used even for viewing closer objects like planets.
For a person with a moderate budget, a Barlow lens is a viable option. The design provides average quality but is a good bargain. It does not burn a hole in one's pocket, and yet is not of inferior quality because of its cost. The range at which this lens is available starts at a low $30 and goes up to $70. The magnification factor is generally not enough for professional use, however for amateurs it should be enough. For hobbyists, it is an ideal lens.
When you're looking for lenses for a telescope, it is important that you determine criteria that most comprehensively fulfill your needs from the lens. Adjustable lenses is a good option as it means you can view objects which are not too far, as well as distant stars with it, and thus obtain the best deal your money can buy you.
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Antique Military Telescopes Old Sailor Sights

Antique military telescopes are available to you as replicas, through several Web sites.
At these replica sites for antique military telescopes you can purchase great replicas of antique military telescopes that were used on ships and other military vehicles. You might find, for instance huge antique military telescopes that were used as port masters or small ones that were used as spyglasses. In most cases, these replicas of antique military telescopes are not only attractive keepsakes but working telescopes as well.
The $44 spyglass telescope, for example, has a fine finish and a classic look. It is tiny enough to fit inside your pocket but when you unfold it it stretches to 14 inches. This smallest of the antique military telescopes has great optics. Its rosewood covering gives it an attractive look as well as comfortable grip. The lens on this spyglass telescope is protected from damage by a cap made of brass.
At the other end of the size spectrum of these antique military telescopes is the Port Master Telescope. Its cost is $385.
It's massive (40 inches) but attractive, and stands on a gorgeous rosewood tripod. This antique military telescope is so tall that a taller than average adult can still view through it while standing.
The Port Master has a targeting telescope that expands and contracts and is mounted on top of its main tube. Once you have honed in on your celestial (or in this case naval) target, you'll find a sharp clear image of even distant objects. The telescope's positioning instruments bring you very exacting information about your target's angle and its locking screws, which are adjustable, let this antique military telescope move easily. In contrast, it can also lock it in place.
The Port Master telescope weighs more than twenty pounds.
Anne Noonan makes it quick and easy to find the best telescope. Read expert information here.
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Three Types of Telescopes - What are the Advantages

Refractors, Newtonian reflectors and Catadioptrics are the three main types of telescopes. All these different types have the same purpose, but each telescope design does it differently. Collecting light and bringing it to point of focus so it can be magnified and examined with an eyepiece is their goal.

Of the different types of telescopes the refractor is the telescope most people think of when they think of astronomy. This type of astronomy telescope is easy to use and reliable due to the simplicity of design. It requires little or no maintenance. Its great for looking at the different types of lunar, planetary, and binary stars.

Newtonians are a type of telescope, which is also known as catoptrics. This type is different from the other telescopes because it has the lowest per inch of aperture compared to refractors and Catadioptrics, because lenses are more expensive to produce than mirrors, especially in medium to large apertures. Newtonians deliver very bright images and are low in optical aberrations.
Catadoptric telescopes are the most popular type of instrument, with the most modern design, marketed throughout the world in 3 1/2 and larger apertures. Its very good for looking at different planetary, lunar, and binary stars. If you like to take photos with your telescope this type of instrument is excellent for deep sky observing or astrophotography with fast films or CCD's.

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Jeremy Hier is the Business Manager and Webmaster of Best Telescope Guides Jeremy Hier is a freelance writer and regular contributer He likes to offer his advice and tips to consumers looking to purchase meade telescopes and celestron telescopes
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