UCCS Astronomy Lab I
PES 1090 Summer/Fall 2010 Telescope/Optics Lab
name: _____________
1. How do astronomers calculate a telescope's light collecting area (A)? (where r = radius of the telescopes
mirror or lens, and B is "pi" or 3.14159)
A)
B)
C)
D)
2.
A=2Br
A = B r^2
A = 4 B r^2
A = 4/3 B r^3
Telescope A has a mirror twice the diameter of telescope B’s mirror. How does A's light-gathering power
compare to B's?
A) A gathers 1/2 the light that B does.
B) A gathers twice the light that B does.
C) A gathers 4 times the light that B does.
D) A gathers 1/4th as much light as B does.
3.
A telescope's resolving power measures its ability to see
A) Fainter sources.
B) More distant sources.
C) Finer details in sources.
D) Larger sources.
4.
One way to increase the resolving power of a telescope is to:
A) Make its mirror bigger.
B) Make its mirror smaller.
C) Replace its mirror with a lens of the same diameter.
D) Observe objects using longer wavelengths.
5.
What causes the image of a star to “twinkle” or scintillate?
A) Irregularities in the density of layers of Earth’s atmosphere, rapidly refracting the light.
B) The flickering fusion process in the stars.
C) A purely physiological reaction in the eye.
D) None of these answers are correct.
6.
What process limits a telescope's resolving power?
A) Reflection
B) Refraction
C) Diffraction
D) Distraction
7.
What is the difference between a reflecting and a refracting telescope?
A) A reflecting telescope uses a lens to focus light; a refracting telescope uses a mirror.
B) A reflecting telescope uses a mirror to focus light; a refracting telescope uses a lens.
C) Both use a mirror to focus light, but a reflecting telescope uses mirrors elsewhere to bend light.
D) There is no difference. "Refracting" is an outmoded way of saying "reflecting."
8.
Light travels __________ in water than in air
A) Faster
B) Slower
C) At the same speed
D) Perpendicular to
9.
Which of the these is a reason for using mirrors rather than lenses in telescopes?
A) Lenses are more expensive to make than mirrors.
B) Most transparent materials focus light of different colors to different spots.
C) Lenses can only be supported by their edges, making them sag in the middle (mirrors can be supported from
behind).
D) All of the above.
10.
Why use an interferometer?
A) Its two widely-spaced mirrors act like one giant telescope with increased collecting area.
B) Its two widely-spaced mirrors act like one giant telescope with increased resolving power.
C) By putting one mirror above the other you can make the instrument much smaller.
D) It can detect light at wavelengths not available to single telescopes.
11.
Which of the following astronomical objects emit radiation mostly at non-visible wavelengths?
A) Dust clouds in space
B) Hot gas surrounding black holes
C) Cold interstellar gas clouds
D) all of the above
12.
Do astronomers use ground-based X-ray telescopes?
A) Yes, because they can penetrate gas clouds.
B) No, because no astronomical objects emit x-rays.
C) No, because x-rays cannot get through the Earth's atmosphere.
D) No, because astronomers have not yet devised detectors for x-rays.
13.
Why does the useful resolving power of a ground-based telescope not match it's theoretical value?
A) Mirrors can't be built accurately enough.
B) The atmosphere blurs the image, decreasing the resolving power.
C) Mirrors cannot collect enough light to reach their theoretical expectations.
D) The theoretical value can only be reached when there is a Full Moon.
14.
On some telescopes, actuators on the mirror change its shape to match distortions in the atmosphere. What
is this technique called?
A) Actuary observing
B) Interferometry.
C) Refraction
D) Adaptive Optics
15.
Which of the following is a reason to build an observatory in space?
A) They are much less expensive than ground-based observatories.
B) They can last forever.
C) To avoid atmospheric blurring.
D) There is no good reason to build a space-based observatory.
16.
The combination of lenses & mirrors folding the optics & forming an image is called:
a.
b.
c.
d.
17.
A telescopic mount that allows telescopes to swing from horizon to zenith, and pivot to point toward
different compass directions is called a(n):
a.
b.
c.
d.
18.
ALT-AZ Mount
Prime Meridian Mount
Equatorial Mount
Polar Mount
Refraction makes astronomical objects look __________ in the sky than they actually are.
a.
b.
c.
d.
20.
Equatorial Mount
ALT-AZ Mount
Prime Meridian Mount
Polar Mount
A(n) __________ has pivot its axis that can be positioned so it points at the celestial pole, and swings up and
down from polar axis until it matches the objects declination, & then it pivots telescope to match the R.A.
a.
b.
c.
d.
19.
Catadioptrics
Plossl
Meade
Newtonian
Lower
Higher
Dimmer
Brighter
Identify from the following image the telescope’s focusing type:
a.
b.
c.
d.
Schmidt-Cassegrain
Maksutov-Cassegrain
Dobsonian
Newtonian
21.
Identify from the following image the telescope’s focusing type:
a.
b.
c.
d.
22.
You can find the magnification of a telescope-eyepiece combination by:
a.
b.
c.
d.
23.
(aperture diameter) (eyepiece focal length)
(eyepiece focal length) (f-ratio)
(aperture diameter) (f-ratio)
(size of mirror) (f-ratio)
The optic nerve transmits electrical impulses from the __________ to the brain.
a.
b.
c.
d.
25.
Dividing the telescope’s focal length by the eyepiece focal length.
Dividing the eyepiece focal length by the telescope’s focal length.
Multiplying the telescope’s focal length by the eyepiece focal length.
Multiplying the eyepiece focal length by the telescope’s focal length.
The telescope’s focal length is found by multiplying the:
a.
b.
c.
d.
24.
Schmidt-Cassegrain
Maksutov-Cassegrain
Dobsonian
Newtonian
Iris
Retina
Pupil
Cornea
Photoreceptors called cones are densely packed within the fovea, the very center portion of the __________.
a.
b.
c.
d.
Optic nerve head
Cornea
Sclera
Macula