Refractors use a concave lens to refract the light rays through the main body, off the rectangular prism and into the eyepiece. These telescopes use no mirrors like reflectors (except the triangular prism contains a small mirror but a triangular prism is optional)
international
all telescopes use a mirror.
Radio telescopes; however, radio telescopes ARE degraded in bad weather. Electrical storms can damage them, and rain in the dish can attenuate the received signal.
Yes. It takes energy to move them in the correct direction. In home telescopes, this is done by hand (energy from your muscles), in large telescopes they use some kind of motors to do that.
To improve resolving power you want your telescope as wide as possible. Lenses larger than one meter are not really feasable while 10 meter mirrors have been built successfully. Lenses focus different colors (wavelengths) of light different places (chromatic abberation) making good imagery difficult. Mirrors don't care about the wavelegth.
hubble
Concave Mirrors
A concave mirror magnifies the image of an item close to it. This type of mirror has a curved surface that causes light rays to converge, creating a magnified image of objects placed near it. Concave mirrors are commonly used in makeup mirrors and telescopes.
international
Concave mirrors in order for the light to be concentrated so that it points forward.
all telescopes use a mirror.
Radio telescopes; however, radio telescopes ARE degraded in bad weather. Electrical storms can damage them, and rain in the dish can attenuate the received signal.
Radio telescopes detect stars known as 'Pulsars'. They're very small and also known as neutron stars.
Yes. It takes energy to move them in the correct direction. In home telescopes, this is done by hand (energy from your muscles), in large telescopes they use some kind of motors to do that.
objective complement
X-rays mirrors can be built, but only if the angle from the plane of reflection is very low (typically 10 arc-minutes to 2 degrees). These are called glancing (or grazing) incidence mirrors. In 1952, Hans Wolter outlined three ways a telescope could be built using only this kind of mirror. Not surprisingly, these are called Wolter telescopes of type I, II, and III. Each has different advantages and disadvantages.
They use convex mirrors to give a wider view.