Expert: Tom Whiting - 10/21/2008

Question
I need help again, I would really appreciate it
WHICH WORD BELONGS TO WHICH SENTENCE?

1.The ____of the Hubble telescope is better for shorter (bluer) wavelengths of light than for longer (redder) wavelengths of light.

2.The large research observatories on Mauna Kea use giant____.

3.____ Separate various colors of light, allowing astronomers to determine stellar composition in many other stellar properties.

4.The 10-m Keck telescopes can work together to obtain better angular resolution through a technique known as____.

5.The Chandra X-ray observatory focuses X-rays with ____ mirrors.

6.A 10-meter telescope has a larger____ than a 4-meter telescope.

7.Galileo’s telescopes design using lenses were examples of____.



-Grazing Incidence
-Spectrographs
-Angular resolution
-Refracting telescopes
-Light-collecting area
-Interferometry
-Reflecting telescopes


-ALSO-

Listed following are distinguishing characteristics and examples of reflecting and refracting telescopes.

-Incoming light passes through glass
-Very large telescopes became “top heavy”
-Galileo’s telescope
-Most commonly used by astronomers today
- The worlds largest is 1-meter in diameter
-The Hubble Space telescope
-World’s largest telescope

Which ones belong to the “Reflecting Telescopes” and which ones belong to the “Refracting Telescopes”


Answer
In reverse order,
7. a refracting telescope.
6. light collecting area.
5. grazing incidence mirrors (X-rays would travel right straight thru glass parabolic mirrors.)
4. Interferometry, which uses 2 widely separated telescopes to
collect the light.
3. Spectrographs
2. Reflecting telescopes
1. Angular resolution (fine detail) because it's up above the
turbulent atmosphere.

Refracting (lens up front) scopes....
1. Incoming light passes through the glass and the light is bent
(Refraction means....to bend)
2. Very large refractors become top heavy with the lens up front...
but this is not why the Yerkes 1 meter refractor in Williams Bay,
Wisconsin.... is the largest ever built, and there will never be a bigger refractor...with a lens on top (up front) you can only support a large lens on its perimeter. Above a 40 inch diameter, the glass will sag under it own weight and deform, thus rendering the image worthless!
3. Galileo used a small refractor, because the standard Newtonian
Reflector, using a mirror, and invented by Sir Isaac Newton, was still about 100 years later.
5. Largest is 40 inches (one meter)...the Yerkes Refractor as mentioned above.

All the rest are reflectors, using a mirror at the bottom...
World's largest, the Hubble scope, and the one most commonly used
by astronomers today.
You probably already knew most of this stuff.
But, Hope it helps,
Clear Skies
Tom Whiting
Erie, PA