ASTR 101-3, FALL 2010 1

LECTURE 7, SEPTEMBER 14, 2010

ASTR 101, SECTION 3INSTRUCTOR, JACK BRANDT

jcbrandt@unm.edu

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Question 1

Modern telescopes use mirrors rather than lenses for all of these reasons EXCEPT

a) light passing through lenses can be absorbed or scattered.

b) large lenses can be very heavy.c) large lenses are more difficult to make.d) mirrors can be computer controlled to

improve resolution.e) reflecting telescopes aren’t affected by the

atmosphere as much.

Question 1

Modern telescopes use mirrors rather than lenses for all of these reasons EXCEPT

a) light passing through lenses can be absorbed or scattered.

b) large lenses can be very heavy.c) large lenses are more difficult to make.d) mirrors can be computer controlled to

improve resolution.e) reflecting telescopes aren’t affected by the

atmosphere as much.

Reflecting instruments like the KECK telescopes can be made larger, and more capable, than

refractors.

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Question 4

Resolution is improved by using

a) larger telescopes & longer wavelengths. b) infrared light.c) larger telescopes & shorter wavelengths. d) lower frequency light.e) visible light.

Question 4

Resolution is improved by using

a) larger telescopes & longer wavelengths. b) infrared light.c) larger telescopes & shorter wavelengths. d) lower frequency light.e) visible light.

Diffraction limits resolution; larger telescopes and shorter-wave light produces sharper images.

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a) the quality of the telescope’s optics.b) the transparency of a telescope’s lens.c) the sharpness of vision of your eyes.d) the image quality due to air stability.e) the sky’s clarity & absence of clouds.

Seeing in astronomy is a measurement of

Question 2

Seeing in astronomy is a measurement of

Question 2

“Good Seeing” occurs when the atmosphere is clear and the air is still.

Turbulent air produces “poor seeing,” and fuzzier images.

a) the quality of the telescope’s optics.b) the transparency of a telescope’s lens.c) the sharpness of vision of your eyes.d) the image quality due to air stability.e) the sky’s clarity & absence of clouds.

Point images of a star

Smeared overall image of star

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Question 8

Radio telescopes are useful because

a) observations can be made day & night.b) we can see objects that don’t emit visible

light.c) radio waves are not blocked by interstellar

dust.d) they can be linked to form interferometers.e) All of the above are true.

Question 8

Radio telescopes are useful because

a) observations can be made day & night.b) we can see objects that don’t emit visible

light.c) radio waves are not blocked by interstellar

dust.d) they can be linked to form interferometers.e) All of the above are true.

The Very Large Array links separate radio telescopes

to create much better resolution.

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Question 9

Infrared telescopes are very useful for observing

a) pulsars & black holes.b) from locations on the ground.c) hot stars & intergalactic gas.d) neutron stars. e) cool stars & star-forming regions.

Question 9

Infrared telescopes are very useful for observing

a) pulsars & black holes.b) from locations on the ground.c) hot stars & intergalactic gas.d) neutron stars. e) cool stars & star-forming regions.

Infrared images of star-forming “nurseries” can reveal objects still

shrouded in cocoons of gas and dust.

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REVIEW-CHAPTER 0

• Foundations of Astronomy• Scientific Method, Powers of 10• Celestial Sphere, Seasons• Angles, Ecliptic• Precession• Moon Phases, Eclipses• Parallax

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REVIEW, CHAPTER 1

• Geocentric vs. Heliocentric Solar System• Famous Names in Historical Astronomy &

Their Contributions• Copernicus, Galileo, Tycho, Kepler, Newton• Retrograde Motion, Venus Phases• Kepler’s Laws and the AU• Newton’s Laws & Gravitation• Orbits, Masses

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REVIEW, CHAPTER 2

• Light and Its Importance in Astronomy• Wave description vs. Photons• Electromagnetic (EM) Spectrum• Atmospheric Transmission & Windows• Atoms, Absorption & Emission of Photons• Uses of Spectra in Astronomy• Doppler Effect

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REVIEW, CHAPTER 3

• Optical Telescopes, Basic Types• Light Gathering Power• Resolving Power or Resolution• Atmospheric Effects• Radio Telescopes• Infrared (IR) Images• X-Ray Images

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TEST NO. 1, SEPTEMBER 16, 2010

• Multiple Choice, 40 Questions• Paper Copy Plus Bubble Sheet• Paper Copy Will Be Color Coded• Identification Number Is Your Banner Number,

Code It In As “Identification Number” Starting With Column A

• BRING A NO. 2 PENCIL

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TEST NO. 1, SEPTEMBER 16, 2010

• Bring A No. 2 Pencil• Circle Your Answer On the Paper Copy And Fill

In The Bubble Sheet• Turn In Both Copies So The Different Color

Tests Are Graded With The Correct Answer Sheet!

• BRING A NO. 2 PENCIL!