1. Science 9 - Space Topic 4 – Bigger and Smarter Telescopes

2. Astronauts today use spectroscopy to examine stars but to collect enough light to detect a spectrum, astronomers have always needed telescopes. Over the past two centuries, astronomers have built bigger telescopes to look deeper into the universe!!!

3. New Discoveries Bigger telescopes enable astronomers to find NEW astronomical objects Note: In 1773, Sir William Herschel, an English Astronomer, built a large reflecting telescope in Great Britain. Using this telescope, he discovered Uranus. This was an exciting discovery because no on had ever suspected the existence of other planets in the solar system.

4. Combining Telescopes Today, it is now possible for computers to combine images from more than one telescope. This creates the equivalent of one telescope the size of the total distance BETWEEN the two!

5. Adaptive Optics Read pg. 386 The technology that adjusts the mirror in the telescope or adjusts the image of a telescope, to cancel the effects of the constant changes in Earth’s atmosphere Ex: gets rid of the twinkling (blurring) of the stars Analogy: moving while taking a picture

6. Distance to the Stars To find how far stars and celestial bodies are away from Earth, Astronomers use a process called triangulation (parallax technique). Triangulation: a method of measuring distance indirectly by creating an imaginary triangle between an observer and an object whose distance is to be estimated

7. Parallax: is the shift in position compared to stars that are farther away. http://en.wikipedia.org/wiki/File:Parallax.gif an apparent displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two linesapparent position

8. Angle to be measured baseline Point on the distance object Lines drawn from the baseline ends to the point on the distance object Distance to be measured in a scale diagram Angle to be measured

9. Steps in triangulation: 1. Create a baseline- the larger the better 2. Measure the angles from the end of the baseline 3. Make a scale drawing (This is just like a map! Ex: 1cm = 20m)

10. EXAMPLE: How long is the unknown distance to the observatory?

11. Note: In order to use triangulation, you need to know the length of one side of the triangle (baseline) and the size of the two angles

12. To do: pg. 392 #1-3 Triangulation WS