1. Topic: Telescopes PSSA: 3.4.7.D/S8.A.2.2

2. Objective: TLW compare optical and nonoptical telescopes. TLW compare optical and nonoptical telescopes.

3. MI #1: Optical Telescopes Optical telescopes collect visible light from objects in the universe and focus it on a focal point for closer observation. Optical telescopes collect visible light from objects in the universe and focus it on a focal point for closer observation. A focal point is the point where the rays of light that pass through a lens, or that are reflected by a mirror, converge. A focal point is the point where the rays of light that pass through a lens, or that are reflected by a mirror, converge.

4. MI #2: Refracting Telescopes Refracting telescopes use lenses to gather and focus light. Refracting telescopes use lenses to gather and focus light. There are two disadvantages of refracting telescopes….1) they focus different colors of light differently, so the image is not perfectly focused….2) if the objective lens is too big, the image gets distorted. There are two disadvantages of refracting telescopes….1) they focus different colors of light differently, so the image is not perfectly focused….2) if the objective lens is too big, the image gets distorted.

5. MI #3: Reflecting Telescopes Reflecting telescopes use a curved mirror to gather and focus light. Reflecting telescopes use a curved mirror to gather and focus light. One advantage to reflecting telescopes is that the mirrors can be very large. One advantage to reflecting telescopes is that the mirrors can be very large. Reflecting telescopes can also focus all colors of light to the same focal point, so the image is completely focused. Reflecting telescopes can also focus all colors of light to the same focal point, so the image is completely focused.

6. MI #4: Nonoptical telescopes Nonoptical telescopes study objects in space by collecting different wavelengths of EM radiation. Nonoptical telescopes study objects in space by collecting different wavelengths of EM radiation. These telescopes may collect radio waves, infrared, X-rays, or gamma rays These telescopes may collect radio waves, infrared, X-rays, or gamma rays

7. MI # 5: Hubble Space Telescope The Hubble Space Telescope is an optical reflecting telescope that orbits the Earth. The Hubble Space Telescope is an optical reflecting telescope that orbits the Earth. It uses a mirror that is 2.4 meters in diameter to produce exceptionally clear images of deep space objects. It uses a mirror that is 2.4 meters in diameter to produce exceptionally clear images of deep space objects. http://hubblesite.org/gallery/album/show/ solar_system/ http://hubblesite.org/gallery/album/show/ solar_system/ http://hubblesite.org/gallery/album/show/ solar_system/ http://hubblesite.org/gallery/album/show/ solar_system/

8. So What…? Real Life Application Telescopes are one of the most important tools that astronomers use to study the universe. Telescopes are one of the most important tools that astronomers use to study the universe.