Science 9 - Space Topic 4 Bigger and Smarter Telescopes
Slide 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!!!
Slide 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.
Slide 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!
Slide 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 Earths atmosphere Ex:
gets rid of the twinkling (blurring) of the stars Analogy: moving
while taking a picture
Slide 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
Slide 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
Slide 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
Slide 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)
Slide 10
EXAMPLE: How long is the unknown distance to the
observatory?
Slide 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
