In general a reflector is shorter because it "folds" the light at least compared to a refractor of the same diameter. A Reflecting telescope is usually cheaper than a refracting scope of the same diameter.
Refracting telescopes are optical telescopes.
You probably mean "reflecting" telescopes, which use a concave mirror to gather light, and another mirror to direct it to a refracting eyepiece that increases the magnification and focuses the image.
Refracting telescopes tend to be cheaper than reflectors, and can be manufactured with zoom features. Because they are tripod mounted, they can be manually-aimed with more versatility, and can even be used for terrestrial observation with an erecting eyepiece. However, because of their design, they do not gather or transmit as much light as a reflector, and their greater number of lens surfaces tend to degrade the image more than a reflecting telescope of the same power.
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The best type of telescope depends a lot on the size that you choose and the money you spend.
There are advantages to refracting telescopes and disadvantages when compared to reflecting telescopes. One is not automatically better than the other.
First, the basic meaning of the terms we use.
The basic refracting telescope consists of two glass lenses at each end of a tube. The larger lens collects the light from a distant object and the smaller lens directs it the to the iris of the observer's eye. It is called "refracting" because the lenses are curved and the light that enters the lenses is refracted in such a way that it is redirected to a desired point. Two lenses are needed because the large lens collects the rays from the distant object and the second lens magnifies the size of the image for the human eye.
The basic reflecting telescope typically consists of two mirrors. A large mirror, called the primary mirror, is located at the back of the telescope. (Back means the opposite end from the end pointed at the object that you wish to observe.) The primary mirror collects the light and focuses so the smaller mirror, called the secondary mirror, collects the light and reflects it to a size enlarged for the eye of the observer.
Comparisons:
Lens making was a highly refined art well before mirrors could be shaped with the accuracy needed to create an image accurately. (Of course, the reflecting telescope waited to be invented by Isaac Newton, half a century after Galileo.)
Mirrors are lighter than lenses and so a refracting telescope is typically heavier than a refracting telescope.
Lenses suffer from chromatic aberration where the different colors entering the telescope are focused differently thus limiting the precision of a multicolored image. The larger the lens, the more serious the problem. (There exists a type of lens called an achromatic lens which minimizes this problem.) Mirrors do not have this problem. (There is also the more complex issue of spherical aberration which favors the reflecting telescope.)
Refracting telescopes are typically longer, a characteristic that enhances the quality of the image when the larger lens does not have to focus light so strongly.
Reflecting telescopes typically lose some of the light because the secondary mirror is located in a way that blocks the incoming light. This is more of a problem for a smaller telescope.
Large telescopes (in the range of a half meter or more in diameter) are now almost always made with mirrors because the quality of mirrors made today can very high and the cost of a large mirror is much lower than a large lens and the weight is much less.
There are hybrid designs that take advantage of some features of both.
In the final analysis, very small telescopes of a few centimeters to perhaps a few tens of centimeters, can be high quality and not too expensive. Lens making is an advanced art and small lenses are relatively cheap and easy to use. In the range of ten to thirty centimeters, it is very common to see the hybrid styles when collecting more light is desired and the smaller lighter hybrid, which does light collection with a mirror, works well. The largest telescopes are all mirror telescopes. Lenses have weight and engineering issues and become too expensive when sizes exceed 30 to 40 centimeters. For large telescopes, one wants to collect a very large amount of light and the issue of portability does not matter because these are large fixed and expensive.
These are all general statements and include judgements about what constitutes large, high quality and expensive, so variations of opinion on what is "better" will exist.
first of all, it is much cheaper, second, it is much better as details go
The Advantages are that they are nice and light.
you can see space maybe? people should start amnswerig things like this
Those two particular categories of equipment have
essentially identical functionality and characteristics.
I think the question meant to say "over refractors".
They offer extreme magnifications of the Skies overhead, and thereby provide extreme close up views of real objects millions and billions of miles [kilometers = miles *1.6] away.
It is in the Indian Astronomical Observatory in Hanle in India.
Prior to being launched into space on 23 Jul 1999 on STS-93, the Chandra X-Ray Observatory (CXO) was given an expected lifetime of 5 years. In September 2001 NASA extended the CXO's lifetime to 10 years "based on the observatory's outstanding results." Physically the observatory could last for much longer. A study performed at the Chandra X-ray Center indicated that the CXO could last at least 15 years. Because current technology cannot significantly improve upon the resolving power of Chandra's mirrors, it's unlikely that another x-ray observatory will be launched before 2015. So we'll probably get to see just how long Chandra can last.
The Hubble space telescope uses optical sensors to gather data of distant objects; as it is located outside of the Earths atmosphere it is not subject to the distortions associated with terrestrial telescopes. The Chandra (X-ray observatory) gathers x-ray data about the universe; again, this cannot be achieved with terrestrial based observatory instruments
x-rays do not penetrate the earths atmosphere there for it has to operate in space in order to view this part of the electromagnetic spectrum
Chandra X-Ray Observatory Cost: Development ~ $1.65 billion Launch Costs ~ $350 million Operations and Data Analysis (years 1-5) ~ $0.75 billion Operations and Data Analysis (years 6-10) ~ $245 million
Unmanded mission:)
the mission was to find white dwarfs a category of stars
Because X-Rays do not penetrate the earth's surface. The Chandra X-Ray Observatory would be completely useless on the ground because it detects X-Rays. Therefore, it must be in space to detect the rays.
There are four: Hubble Space Telescope, Compton Gamma Ray Observatory, Chandra X-ray Observatory, and the Spitzer Space Telescope.
It is in the Indian Astronomical Observatory in Hanle in India.
Prior to being launched into space on 23 Jul 1999 on STS-93, the Chandra X-Ray Observatory (CXO) was given an expected lifetime of 5 years. In September 2001 NASA extended the CXO's lifetime to 10 years "based on the observatory's outstanding results." Physically the observatory could last for much longer. A study performed at the Chandra X-ray Center indicated that the CXO could last at least 15 years. Because current technology cannot significantly improve upon the resolving power of Chandra's mirrors, it's unlikely that another x-ray observatory will be launched before 2015. So we'll probably get to see just how long Chandra can last.
Columbia was launched on 23rd July 1999 carrying the Chandra X-ray Observatory
The Hubble space telescope uses optical sensors to gather data of distant objects; as it is located outside of the Earths atmosphere it is not subject to the distortions associated with terrestrial telescopes. The Chandra (X-ray observatory) gathers x-ray data about the universe; again, this cannot be achieved with terrestrial based observatory instruments
The Hubble space telescope uses optical sensors to gather data of distant objects; as it is located outside of the Earths atmosphere it is not subject to the distortions associated with terrestrial telescopes. The Chandra (X-ray observatory) gathers x-ray data about the universe; again, this cannot be achieved with terrestrial based observatory instruments
they use gamma rays... i think. top that peeps!
x-rays do not penetrate the earths atmosphere there for it has to operate in space in order to view this part of the electromagnetic spectrum
Chandra X-Ray Observatory Cost: Development ~ $1.65 billion Launch Costs ~ $350 million Operations and Data Analysis (years 1-5) ~ $0.75 billion Operations and Data Analysis (years 6-10) ~ $245 million