Telescopes and Space Probes Flashcards

1
Q

What are the two basic telescopes?

A

Reflectors and refractors

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2
Q

What type of lens does a refracting telescope use?

A

Convex Lens

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3
Q

What type of lens does a reflecting telescope use?

A

Parabolic (Concave) Lens

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4
Q

What does an objective element do?

A

It collects as much light as possible and focuses it into a small, bright image

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5
Q

What does an eyepiece lens do?

A

An eyepiece lens magnifies the image given by the objective element so we can see an image in high resolution

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6
Q

What are the differences with a larger telescope?

A
  • More light enters the telescope; making the image brighter

- There is a higher resolution and a bigger amount of detail

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7
Q

What does the resolution depend on (in terms of wavelengths)?

A

The wavelength of light that is entering the telescope; a red nebulae has a lower resolution compared to a blue nebulae as red has a longer wavelength

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8
Q

What determines a telescope’s magnification?

A

The ratio of the lengths of the objective and and eyepiece

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9
Q

What is the equation for magnification?

A

. . . . . . . . . . . . . . .focal length of objective. . . fo
magnification = ———————————– = —-
. . . . . . . . . . . . . . .focal length of eyepiece. . . fe

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10
Q

Name two ways you can get greater magnification

A
  • Use eyepieces of different focal lengths; the shorter the focal length, the greater the magnification
  • Use a Barlow Lens
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11
Q

What is a Barlow Lens?

A

A Barlow lens a piece of kit for astronomers that slots into the eyepiece and increases the magnification by 2x or 3x

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12
Q

What is Field Of View (FoV)?

A

The field of view of a telescope is the circle of the sky that is visible through the eyepiece

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13
Q

What is a parabolic mirror?

A

A concave mirror that transforms a plane wave into a spherical wave that moves into the centre

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14
Q

What are the 4 main sources of light pollution?

A
  • Commercial and sports floodlights
  • Urban street lamps and motorway lights
  • Domestic and industrial security lights
  • Lights above car parks and shopping centres
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15
Q

How long is 1 AU?

A

1 AU = 150 Million km = Distance from the Earth to the Sun

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16
Q

How long is one light year?

A

1 l.y. = 9,500,000,000,000 km= 9.5 billion km

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17
Q

How long is one Parsec?

A

1 pc = 3.26 l.y. = 3.1 × 10¹³ km

18
Q

What is an H-Alpha Filter?

A

An H-Alpha filter is a filter which is designed to transmit a narrow bandwidth of light. It can be used to observe the features of the Sun

19
Q

Which photoreceptors in a human eye respond to bright lights?

A

Cones

20
Q

What is the approximate diameter of the pupil of the human eye in bright light?

A

3 mm

21
Q

What is Dark Adaption?

A

Dark Adaption is an observing technique where the observer spends time to allow the retina’s rods to desensitise so dimmer stars become more visible

22
Q

What are the components of a reflecting telescope?

A

A reflecting telescope consists of a Concave mirror and Convex lens

23
Q

What is the objective element of a reflecting telescope?

A

Converging mirror

24
Q

Which telescope does an observer not look along its optical axis?

A

Newtonian Reflector

25
Q

Which telescope uses a small diverging secondary mirror to reflect to reflect light back down the ‘tube’?

A

Cassegrain Reflector

26
Q

What is a finderscope?

A

A finderscope is a smaller telescope attached to larger reflectors

27
Q

What is more important: Resolution or Magnification

A

Resolution

28
Q

How is a Keplerian refractor different to a Galilean refractor?

A

A Keplerian refractor consists of two concave lenses whereas, a Galilean refractor has one

29
Q

What is the resolution of a telescope proportional to?

A

Resolution of a telescope proportional to the diameter of the objective element

30
Q

A small inexpensive telescope would be most likely what type of telescope?

A

Keplerian Refractor

31
Q

What are the advantages of having a reflecting telescope over a refractor?

A
  • Higher magnifications
  • Larger objective diameters
  • Shorter physical lengths
32
Q

What was the space probe Magellan’s target?

A

Venus / Orbiter

33
Q

What was the space probe New Horizon’s target?

A

Pluto & outer Solar System / Fly-by

34
Q

What was the space probe Deep Impact’s target?

A

Comet Tempel 1 / Impactor

35
Q

What was the space probe Juno’s target and what type of probe was it?

A

Jupiter / Orbiter

36
Q

What was the space probe Huygens’ target and what type of probe was it?

A

Titan / Lander

37
Q

Which space probe made detailed studies of asteroids Vesta and Ceres from orbit?

A

Dawn

38
Q

What are the advantages of a unmanned mission compared to a manned mission?

A

Unmanned missions are cheaper, there is no danger faced towards humans and there are no communication time delays as the mission is pre-programmed with mission commands without the need for human interference

39
Q

Which twin space probes studied the outer gas planets, their ring systems and moons?

A

Voyager

40
Q

What was the space probe Philae’s target and what type of probe was it?

A

76P/Churyumov-Gerasimenko / Lander

41
Q

What was the Purpose of Philae?

A
  • To make detailed studies of the surface of a comet (including an analysis of its water).
  • A chemical composition of comet’s surface (including ammonia, hydrogen cyanide and hydrogen sulfide)
  • Discovery of amino acids in ‘haze’ around the nucleus
  • The shape of comet implied that it was initially two separate bodies that fused together billions of years ago
  • Analysis of water content found much larger abundance of H-2 isotope (deuterium) suggesting water was not deposited on Earth by comets.