Bang for the buck. When you need to collect a lot of light to see faintcelestial objects clearly, a large mirror is cheaper and easier to manufacture without defects than asimilarly sized refracting lens.
We use telescopes or satellites
Most optical telescopes used by professional astronomers are located on mountains or remote locations away from city lights to minimize light pollution and atmospheric disturbances. Some observatories, such as those in Chile and Hawaii, are known for having excellent observing conditions due to high altitudes and clear skies. Telescopes are also placed in space, like the Hubble Space Telescope, to avoid atmospheric interference.
The most serious astronomical research, such as that done by the Hubble Space Telescope, is done with reflecting telescopes.
Reflecting telescopes are far-and-away the most common. This is because the telescope can be smaller and lighter, and because lenses always absorb a little light while mirrors can be almost perfect reflectors.
A reflecting telescope is much easier to build than a refracting telescope and consequently is much less expensive. A reflecting telescope uses a concave mirror to collect and concentrate starlight and send it to your eye, whereas a refracting telescope uses a series of lenses to do the same thing. Optical quality lenses are much more expensive (and heavier) than a well-made mirror. For a given amount of money, much larger reflecting telescope can be built than a refracting. For very large telescopes, the lenses needed would be enormous and next to impossible to make optically perfect. Consequently, most telescopes are reflecting.
observeries?
They are refracting telescopes(:Large refracting telescopes are no longer built because there were too many problems with them. There was color distortion, light pollution, and when the object hits the focal point it turns upside down. Then you don't see the object for what it really is, you see it upside down and weird-ed out. They are to complicated and scientists believed they should just stick with the simple, small, original refracting telescopes!!!!-Meghan Betts (8th grader)
Very little astronomy is still done by physically looking through telescopes, so astronomers can basically work any hours they want. The really large telescopes are quite expensive and tend to be shared (and located in remote, desolate places). Most astronomers rely on dedicated on-site staff at the scope who collect images or data for the astronomers to analyze later.
Most telescopes collect and focus light from distant objects in space, such as stars, planets, and galaxies. This focused light is then magnified and analyzed by astronomers to study and make observations about the universe.
If they have been observing at night, yes - rather like shift workers. However most astronomers no longer observe directly but use cameras that are much more sensitive than the human eye to obtain their telescope data. This allows telescopes to be automated and the data save so that astronomers can analyse it during the day without having to visit the telescope. These astronomers work normal hours and only a few are needed to man the telescopes (a task which may also be done remotely).
They are much shorter than refracting telescopes, hence, much cheaper to buy and easier to transport.
refracting