Observing and exploring space Chapter 1.1 Telescopes Part 2

How are we… able to see the color of Saturn’s Rings? able to tell that the moon has craters You could use a device called a telescope. Telescope- is an instrument that gathers electromagnetic radiation from objects in space and concentrates it for better observation

Optical Telescopes Most common of telescopes. The optical telescope collects visible light and focuses it to a focal point for closer observation Focal Point- the point where rays of light that pass through a lens or that reflect from a mirror and meet.

Refracting Telescopes Refracting Telescopes- uses a set of lenses to bend and focus light Galileo helped to build these The earliest telescopes were all refractors

Disadvantages of Refractors These are good to observe objects within our solar system Since light is refracted… Images are not always focused Refracting telescopes need to be stronger in order to support the heavy glass

Reflecting Telescope ~ 1670 Sir Isaac Newton built a different kind Reflecting Telescope- uses a set of curved mirrors to gather and focus light from distant objects. Largest optical telescopes are Reflectors

Why reflecting telescopes? Mirrors are lighter, so they are able to be larger The larger the mirror the more light being gathered Flaws in the glass does not affect light because curved mirrors are polished.

Radio Telescopes Very large and look like satellite dishes The telescopes below are linked together by a computer

Arecibo Observatory Largest Radio Telescope located in Puerto Rico

Earths Atmosphere and Telescopes Why do you think most observatories are located on high mountains? Light pollution blocks some of the radiation Atmosphere distorts the light which is why some stars seem to twinkle Where would be the best location to place a telescope?

Space Telescopes Space telescopes have no interference since they orbit outside of the atmosphere Hubble telescope has been orbiting since 1994

What did we do before Telescopes? The sky has been studied for thousands of years Motion of the stars helped keep track of seasons Stars were so important that they were placed into Constellations, patterns in the sky Greek astronomers saw “stars” move across the constellations know now as Planets

Galileo’s Observations In 1610 Galileo look at the night sky and began his discoveries of the following More to the night sky and the Milky way is made up of many stars Moon has craters Venus has phases Jupiter has moons Sun has dark spots Now, we can use binoculars to study this information