About Telescopes
A telescope is an instrument -- usually optical -- used in astronomy for observing distant objects
In this lens, we present some of the best guides for buying a telescope and also select the best deals on the best 'scopes for you.
The Best Telescope Buying Guides
- SPACE.com -- How to buy a telescope: accessories, gadgets, constraints
- So you want to buy a telescope or are at least flirting with the idea. Your problem: you know less than Galileo about lenses, tubes, etc. Before buying anything -- breathe in, breathe out and check out our idiot's guide to scoping out scopes.
- Telescopes - Buying and Using a Telescope
- Star gazing is a favorite part of astronomy for many people. However, star gazing can be done easily with the naked eye. What most people really want to do is use a telescope to view other planets, and some deep space objects that can not be easily seen with the naked eye. If you have already spent
- 6 Things To Know About How To Buy a Telescope for Telescope Astronomy
- So, you want to know how to buy a telescope. Being a knowledgeable consumer is key Before you go shopping, learn as much as you can about telescopes. We will try to help you get started here, with the six things you need to know about how to buy a telescope.
6 Things To Know About How To Buy a Telescope From Nick Greene
- Power - A good scope will not talk about its "Power": If the box blares "300X" or other numbers about the "Power" the scope within has, Caution! High power sounds great, but, there's a catch. While high magnification makes an object appear larger, light gathered by the scope is spread over a larger area creating a fainter image. Also, "high-powered" scopes have restrictions of the eyepiece design, which may limit how much of the large image you can actually see. Sometimes, lower power provides a better viewing experience.
- Refractor/Reflector - Advantages and disadvantages to each type: A refractor uses two lenses. At one end, is the larger lens, called the objective. On the other end is the lens you look through, called the ocular or eyepiece. A reflector works a bit differently. Light is gathered at the bottom of the telescope by a concave mirror, called the Primary, which has a parabolic shape. There are many ways the primary can focus the light, and how it is done determines the type of reflecting scope. Read more about the types of scopes: Telescope.
- Aperture - Aperture size is the true key to the "power" of a telescope: The aperture of a scope refers to the diameter of either the objective lens of a refractor or objective mirror of a reflector. The aperture size is the true key to the "power" of a telescope. Its ability to gather light is directly proportional to the size of its aperture and the more light a scope can gather, the better the image you will see.
OK, so you're thinking, "I'll just buy the biggest telescope I can afford." Unless you can afford to invest in your own observatory as well, don't go too big. A small scope you can transport will probably see a lot more use than a larger one you don't feel like hauling around.
Typically, 2.4 inch (60mm) and 3.1 inch(80mm) refractors and 4.5 inch and 6 inch reflectors are popular for most amateurs. - Focal Ratio - Know a Telescope's Focal Ratio: The focal ratio is calculated by dividing aperture size into its focal length. The focal length is measured from the main lens (or mirror) to where the light converges to focus. As an example, a scope with an aperture of 4.5 inches and focal length of 45 inches, will have a focal ratio of f10.
While a higher focal ratio does not always mean a higher quality image, it often means as good an image for similar cost. However, a higher focal ratio with the same size aperture means a longer scope, which can translate into transportation woes. - Mount - Necessary for steady viewing: It's likely you never even considered a mount when you thought of buying a telescope. Most people don't. However, the mount is a very important part of a scope.
Some kind of stand to hold the scope steady is essential. It is extremely difficult, if not impossible, to view a distant object if the scope is not very steady. Most people do not have that steady of a grip.
There are basically 2 types of mounts, altazimuth & equatorial. Altazimuth is similar to a camera tripod. It allows the telescope to move up and down (altitude) and back and forth (azimuth). The equatorial is designed to follow the movement of objects in the sky. Higher end equatorials come with a motor drive to follow the rotation of the Earth, keeping an object in your field of view longer. Many equatorial mounts come with small computers, which aim the scope automatically. - Eyepieces - Power is not the object: Your new scope should have at least 1 eyepiece, and often 2 or 3. An eyepiece is rated by millimeters (mm), with smaller numbers indicating higher magnification. A 25mm eyepiece is common and appropriate for most beginners.
Earlier, discussing power, I said a telescope's power or magnification is not the best indicator of a good scope. As with the whole, so the parts. A higher power eyepiece does not mean better viewing. Higher and lower power eyepieces each have their place in observing.
While a higher magnification eyepiece may provide more details, it may be harder to keep an object in view, unless you are using a motorized mount. They also require the scope to gather more light to provide a clearer image.
A lower power eyepiece makes it easier to find objects and keep them in view. Lower magnification eyepieces require less light, so viewing dimmer objects is easier.
Excerpted from: "Buying and Using a Telescope" From Nick Greene on About.Com
Great Stuff on Amazon
Orion SpaceProbe 130 EQ Reflector Telescope
Amazon Price: $239.95 (as of 10/10/2008)
Meade - 16" f/10 LX200GPS-SMT go-to altazimuth, with permanent pier
Amazon Price: (as of 10/10/2008)
Meade - 14" RCX400 Advanced Ritchey-Chrétien with UHTC Coatings
Amazon Price: (as of 10/10/2008)
Celestron NexStar 130 SLT Computerized Telescope
Amazon Price: $439.00 (as of 10/10/2008)
Celestron NexStar 8 SE Telescope
Amazon Price: $1,399.00 (as of 10/10/2008)
Science Gifts
- Science Gifts Guide
- Science Gifts Guide on Mind Media
Great Deals on Telescopes
Meade 80mm Telescope with Tripod (MD207)
10% off any order, with no minimum! Good until April 30thUse code April10 at checkout.
telescopes on eBay
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Astronomy from Wikipedia
Astronomy (from the Greek words astron (??????), "star", and nomos (?????), "law") is the scientific study of celestial objects (such as stars, planets, comets, and galaxies) and phenomena that originate outside the Earth's atmosphere (such as the cosmic background radiation). It is concerned with the evolution, physics, chemistry, meteorology, and motion of celestial objects, as well as the formation and development of the universe.
Astronomy is one of the oldest sciences. Astronomers of early civilizations performed methodical observations of the night sky, and astronomical artifacts have been found from much earlier periods. However, the invention of the telescope was required before astronomy was able to develop into a modern science. Historically, astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, the making of calendars, and even astrology, but professional astronomy is nowadays often considered to be synonymous with astrophysics. Since the 20th century, the field of professional astronomy split into observational and theoretical branches. Observational astronomy is focused on acquiring and analyzing data, mainly using basic principles of physics. Theoretical astronomy is oriented towards the development of computer or analytical models to describe astronomical objects and phenomena. The two fields complement each other, with theoretical astronomy seeking to explain the observational results, and observations being used to confirm theoretical results.
Amateur astronomers have contributed to many important astronomical discoveries, and astronomy is one of the few sciences where amateurs can still play an active role, especially in the discovery and observation of transient phenomena.
Old or even ancient astronomy is not to be confused with astrology, the belief system which claims that human affairs are correlated with the positions of celestial objects. Although the two fields share a common origin and a part of their methods (namely, the use of ephemerides), they are distinct.
