1. Prepare your scantron: Please take a moment to mute your cell phone!
Use
a pencil,
not a pen!
Fill in your name and fill the bubbles under
your name.
LAST NAME FIRST, First name second
Put your 4-digit code instead of “IDENTIFICATION NUMBER”.
--- (The last 4 digits of your OleMiss ID.)
P/f coming – tomorrow
Question # 1: answer A
Question # 2: answer B
Question # 3: answer B
Setup:
Reading assignment
Chapter 14, pp
(The Sun)
Please take a moment to mute your cell phone!

2. This question counts double!
sec 10 9 11 12 15 14 13 8 7 1 2 3 5 4 6 16 26 17 27 28 30 29 24 25 19 18 23 20 22 21
Question 4
This question counts double!
Which of the following limits the magnification of all but the smallest telescopes?
A Inaccurate tracking.
B Quality of the lens/mirror.
C The shaking of the telescope mount.
D Seeing.
E Diffraction.
Next question coming …

3. This question counts double!
sec 8 9 11 7 10 6 1 2 3 4 13 12 14 30 35 40 25 19 16 15 17 18 45 20 5
Question 6
This question counts double!
What is an equatorial mount?
A A design of the telescope’s mechanics that allows
tracking stars in the sky. One axis points straight up).
B A design of the telescope’s mechanics that allows
tracking stars in the sky. One axis points at the North Pole.
C A scientific term that explains the motion of stars in the sky.
D A design of a telescope’s optics with a mirror to collect the light.
E A design of a telescope’s optics with a lens to collect the light.
Next question coming …

4. This question counts double!
sec 8 9 10 12 11 7 6 1 2 3 4 13 30 35 40 45 14 25 16 15 18 17 19 20 5
Question 7
This question counts double!
What is adaptive optics?
A When the telescope follows the stars as they
move in the sky.
B When some of the telescope’s lens or mirror is covered according to changes in the atmosphere.
C When the shape of the optics is changed according to the changes in the atmosphere.
D When appropriate color filters are used as the atmosphere absorbs more or less red or blue light.
E When the magnification of the telescope is chosen according to how turbulent the atmosphere is on the day of the observation.

5. The professional way of doing astronomy: picture taking and imaging
Visual vs. CCD
(1) Visual observation: always unreliable
Recall the canals on Mars - G. Schiaparelli &P. Lowell

6. The professional way of doing astronomy: picture taking and imaging
CCD
(2) Photography: • reliable • can collect light for a long time
(3) The modern way: CCD imaging
• in CCD chip light moves electrons into pixel
• computer counts electrons in each pixel
and turns numbers into image on screen
Similar to a digital camera but:
• chip is cooled to reduce noise
• computer controlled - image can be much
improved with computerized processing techniques
• many images can be added to improve quality
The CCD revolution after 1995: one can take pictures
even of galaxies with amateur equipment from light-polluted sites.

7. The Helix - a planetary nebula (amateur CCD image)
Helix CCD

8. incredible resolution:
Helix HST
The Helix
A Hubble telescope
CCD image
incredible resolution:
16,000 x 16,000

9. Questions coming …

10. sec 8 9 10 12 11 7 6 1 2 3 4 13 30 35 40 45 14 25 16 15 18 17 19 20 5
Question 8
Why do astronomers no longer look into
their telescopes?
A Because the observer’s body would obstruct the
light in research-grade telescopes.
B Because visual observations are unreliable.
C Because there is dangerous radiation in a research observatory.
D Because large telescopes collect so much light that their eyes
would be damaged.
E Because there is nothing left to discover in optical light;
infrared and X-ray radiation must be observed to make new
discoveries.
Next question coming …

11. sec 8 9 10 12 11 7 6 1 2 3 4 13 30 35 40 45 14 25 16 15 18 17 19 20 5
Question 9
What is a CCD?
A A new type of telescope that replaces reflectors.
B A new type of optical device that replaces the lens or mirror
of a telescope.
C A new type of a telescope mount.
D A new type of a detector that replaces photography.
E A new type of an instrument that separates colors in starlight.
Next question coming …

12. sec 8 9 10 12 11 7 6 1 2 3 4 13 30 35 40 45 14 25 16 15 18 17 19 20 5
Question 10
Which of the following is an advantage of
photography over visual observations in astronomy?
A Film has better resolution than the human eye.
B Film can photograph X-rays, while the human eye
cannot see them.
C Film can collect light for a long time.
D Film can be handled automatically in observatories in remote
high mountains.
E Seeing does not affect film photography.

13. Look at a bunch of planetary nebulae - all Hubble images
The Ant Nebula
Ant

14. Cat’s eye
The Cat’s Eye Nebula

15. Egg
The
Egg
Nebula

16. Hourglass
The
Hourglass
Nebula

17. Eskimo
The
Eskimo
Nebula

18. Many “nebulae” have spiral arms: these turn out different - galaxies
Consist
of stars
Are far
away
(outside
the
galaxy)

19. M66
M83
Galaxies: M33,66,83,104
M104
M33

20. M 100
M 49
M49 and M100

21. Radio telescopes
Advantage: can see radiation from charged particles flying
in magnetic field between stars.
Trouble: needs huge antennas for resolution and sensitivity
Jodrell Bank Radio Observatory
Interferometry:
several antennas to work together
improves resolution
but does not help lack of ‘light’

22. X-ray astronomy - Chandra
Launched: 1999
X-ray sources:
when energetic charged
particles hit magnetic fields
• Supernova explosions
• Supernova remnants
• Black holes in nuclei of active galaxies
• Glow of intergalactic gas

23. Infrared astronomy - Spitzer
Launched: 2003 on solar orbit
Infrared sources:
not-so-hot objects
Infrared light is not absorbed
by interstellar dust as regular
light is: can see through
• Newly forming stars and their protoplanetary dust disks
• The center of the Galaxy (behind dust)
• Interstellar dust glows ( K)
• Small and not-so-hot stars ( K)

24. Centaurus A Centaurus A - an active galaxy at various wavelengths
Optical and radio
X-ray (Chandra)
IR (Spitzer)
Optical: starlight and dust obstruction
Radio: charged particle jets in magnetic field
X-ray: very energetic charged particle jets
in magnetic field
Infrared: cold (~100K) dust glows

25. Questions coming …

26. sec 10 9 11 12 15 14 13 8 7 1 2 3 5 4 6 16 26 17 27 28 30 29 24 25 23 19 18 20 21 22
Question 11
Name an object that we can see in infrared but not in regular light.
A The Sun.
B A supernova.
C A hot star.
D The center of the Galaxy.
E An asteroid.
Next question coming …

27. sec 10 9 11 12 15 14 13 8 7 1 2 3 5 4 6 16 26 17 27 28 30 29 24 25 23 19 18 20 21 22
Question 12
In what wavelength can we see
newly born stars best?
A Radio.
B Infrared.
C Optical.
D X-ray.
E Ultraviolet.
Next question coming …

28. sec 10 9 11 12 15 14 13 8 7 1 2 3 5 4 6 16 26 17 27 28 30 29 24 25 23 19 18 20 21 22
Question 13
What objects can radio telescopes study most efficiently?
A The Moon.
B Interstellar matter.
C Stars.
D Comets.
E The planets.
Next question coming …

29. sec 10 9 11 13 14 8 12 7 2 1 3 4 6 5 15 17 26 25 27 28 30 29 16 24 19 18 23 20 22 21
Question 14
Why do we need to place X-ray telescopes on spaceships?
A Because there is too much disturbing background
X-ray radiation on Earth.
B Because X-ray detectors must be cooled to the
temperature of space.
C Because X-rays get absorbed in the atmosphere.
D Because the gravity of Earth repels X-rays from celestial objects.
E Because we must get the X-ray detectors closer to the stars.

30. Hydrogen (mainly) gas ball
The Sun
Sunspots An
Average
main
sequence
STAR
Surface features:
• sharp edge
(photosphere)
• sunspots
• limb darkening
(we see less deep
down at the edge)
Hydrogen (mainly) gas ball
Hot surface (6000 C)