Quiz 3 Practice

Question 1

refractor

Answer 1

combination of lenses

Question 2

reflector

Answer 2

mirrors instead of lenses

Question 3

angular size

Answer 3

how much of the sky the object takes up

Question 4

angular resolution

Answer 4

a measure of how well a telescope can make out small details

Question 5

“seeing”

Answer 5

wiggles (turbulence) in the atmosphere that limit angular resolution

Question 6

zenith

Answer 6

observer-based coordinate; the point directly above your head that meets the top of the celestial sphere

Question 7

North Star/Polaris

Answer 7

found at the location of the North celestial pole; Polaris is our current North Star

Question 8

celestial sphere

Answer 8

an imaginary sphere extending all around Earth

Question 9

celestial equator

Answer 9

an imaginary equator that extends to the sides of the celestial sphere

Question 10

celestial poles

Answer 10

two celestial poles; the north celestial pole and the south celestial pole

Question 11

altitude

Answer 11

“height” of an object above the observer’s horizon; begins at 0° at the horizon, rises to 90° at the zenith

Question 12

azimuth

Answer 12

angular distance around your horizon; begins at 0° facing due North, extends full 360° NESW around observer’s horizon

Question 13

circumpolar star

Answer 13

stars that never set below the observer’s horizon

Question 14

circumpolar zone

Answer 14

the circumpolar region; a circle with a radius equal to the observer’s latitude

Question 15

equinox

Answer 15

when the ecliptic passes through the celestial equator; causes the Spring and Autumn equinoxes

Question 16

How does apparent motion differ from true motion?

Answer 16

Apparent motion is caused by the Earth’s rotation; objects appear to move because the Earth is moving past them as they rotate. Stars have true motion but it is difficult to measure (can take decades).

Question 17

What are the two main goals of a telescope, and how do we achieve them?

Answer 17

1.) Maximize light (create bigger diameters)
2.) Maximum resolution (a. use mirrors over lenses; b. use multiple telescopes to make one image; c. use a laser to make a fake star and un-wiggling formula)

Question 18

Why are reflectors preferred over refractors?

Answer 18

Refractors are made of lenses that can only be supported on the sides; Can cause distortion of images if the lens is too large and can be very heavy. Reflectors do not mend like lenses and are significantly lighter, you can also add multiple mirrors together to make a bigger mirror

Question 19

Why do we need to send some telescopes to space?

Answer 19

(1) Get above the atmosphere for good seeing

Question 20

What is a false color image and why do we make them?

Answer 20

when we assign colors to wavelengths that aren’t their true wavelengths; helps with measuring depth, different stars, objects, galaxies, and the path of light in space

Question 21

How can we locate Polaris in the night sky?

Answer 21

1.) Look due north, at 0° azimuth
2.) Look up from the horizon to an altitude equal to your latitude on Earth

Question 22

Why does the Sun appear to travel along the ecliptic?

Answer 22

The Sun appears to travel along the ecliptic because the Earth passes the sun each day as it turns on its axis

Question 23

Why aren’t the ecliptic and celestial equator the same?

Answer 23

Ecliptic is the apparent path circular path of the Sun over the course of one year. The celestial equator is an imagined equator of the Earth. Touch twice (equinoxes); at furthest part 23.5° twice a year (solstices)

Question 24

angular resolution formula

Answer 24

θ = (70°)(λ / d)

Question 25

astronomy degrees

Answer 25

astronomers measure how far apart objects appear in the sky by using angles