Chapter 6

In practice, the smallest angular size that one can resolve with a 10-inch telescope is governed by the

Diffraction limit of the telescope

Besides adding adaptive optics to a telescope, what else can be done to reduce the effects of seeing?

Put the telescope at a higher altitude (the height above sea level).

Which of the following is a reason that all large astronomical telescopes are reflecting telescopes?

Reflecting telescopes can be designed to be shorter than refracting telescopes Reflecting telescopes minimize chromatic aberration. Reflecting telescopes are not as heavy as refracting telescopes.

Which is the biggest disadvantage of putting a telescope in space

Space telescopes are much more expensive and riskier than similar ground-based telescopes

The largest astronomical refractor has an aperture of 1 meter. Select all true statements below about why it would be impractical to build an even larger refractor with, say, twice the aperture.

A lens with a 2 m diameter would be very heavy and would deform under its own weight within a few years. The degree of chromatic aberration increases as the focal length gets longer, and this would reduce image quality. The tube would have to be so long that housing and moving it would be extremely difficult, especially because it would be frontloaded with weight.

How many times greater is the light-gathering power of a large astronomical telescope (aperture = 5.00 m) than that of the dark-adapted human eye (aperture = 7 mm)?

Area=π×r^2 x𝜋×(7𝑚𝑚/2)^2=𝜋×(3.5𝑚𝑚×1𝑚/1000𝑚𝑚)^2=3.9×10^−5𝑚^2 We need to convert to the units used for the telescope in order to calculate the ratio of the two. The area of the mirror of the telescope =𝜋×(5.00𝑚/2)^2=19.63𝑚^2 19.63𝑚2/3.9×10^−5𝑚^2=510204.08 times greater

CCD cameras have much higher quantum efficiency than that of other detector,k therefore, CCD cameras

Can generate a signal from fewer photons

What type of mission collects information about multiple planets

Flybys

Why is the Hubble Space Telescope in space instead of on the ground?

It observes in the UV It avoids atmospheric distortion.

If the integration time is long enough to collect the light from this entire animation, what effect would seeing have on the image of the object?

It would blur the light from the object, effectively increasing the angular resolution of the telescope.

High speed computers have become one of an astronomers most important tools, which of the following does not require the use of a high-speed computer

Pointing a telescope from object to object

You are shopping for telescopes online. You find two in your price range. One of these has an aperture of 20 cm, and one has an aperture of 30 cm. Which should you choose, and why?

The 30 cm, because the light-gathering power will be better.

What is not a reason that all large astronomical telescopes are reflectors

The glass doesn't need to be curved

If you had a telescope with the same-sized lens (and same focal length) as the human eye, what would be the benefit of taking an exposure of a steady light source with an integration time of 10 seconds?

The light source would appear brighter in the image.

if a telescope is made larger focal lkength with a smaller aperature...

The telescope will be less able to detect dim objects, and it will be less able to resolvefine detail, especially at longer wavelengths.

Spacecraft are the most effective way to study planets in our solar system because

They can collect more information than is available just form images from Earth

hich does not apply to frelecting telescopes

They observe light that bends through a medium

Which is not an advantage of CCd cameras over photographic plates

They turn photons into protons

refraction

bending of light

Rank each of the following colors by how much each refracts, from most (at top) to least (at bottom). I

blue green red

diffraction

blurring of an image

interferometric array

combine the signals from many telescopes, increasing the effective diameter size, increases resolution

what affect does earths atmosphere have on telescopes

degrades images

diffraction limits

depends on the ratio of wavelength to telescope aperture

focal length in reflector

determined by the path of the light takes reflecting of off the mirros

what is the aperture

diameter of objective lens sets the loight collecting power

spectographs

disperse incoming light into its ccomponent wavelength

focal length

distance between lens and image (longer = larger image)

gravitational waves

distortions in spacetime predicted by relativity, first detected in 2015

CCDS (charges coup[led devices)

electronic detectors record photons on pixels great in quality

first telscope used by who

galielo

who first observed heavens

galileo

CCD cameras have much higher quantum efficiency than other detectors. As a result, CCD cameras can

generate a signal from fewer photons.

Which of the following require the use of a high-speed computer?

generating and testing theoretical model .analyzing images taken with very large CCDs studying the evolution of astronomical objects or systems over time

first telscope created

hands lippershey => saw tow children playing with lens

Rank the following items in order of increasing difficulty of detection.

infrared photons neutrinos gravity waves

Arrays of radio telescopes can produce much better resolution than single-dish telescopes because they work based on the principle of

interference.

what happens when light enters a medium

its speed changes

radio telescopes

large parabolic dishes with antennas

neutrinos

light subatomic particles that are extremely difficult to detect

astronoimica seing

limits resolution due to atmosphereic turbulen

Where are telescopes currently not located

moon

problems with refractors

need to be large structures to have a long focal length lenses suffer from chromatic aberration

types of reflecting telescopes

newtonian prime focus cassegrain coude

does the atmoshpere transmit all light

no

reflectors advanatages over refractors

no chromatic abberation mirrors can be made lighter theta are more compact bigger is brighter = higher resolution

what part of refractor refracts the light

objective lens (placed at end facing sky)

types of mirrors in reflecter

primary and secondary

what telescopes allows astronomorers to stuyd radio waves with wavelenthghs of about 10 centimeters

radio telescopes

resolution

refers to the smallest details that can be separated

two kinds of telescopes

reflectingf and refractin

largest telescopes in the worl are what type

reflectors

Place the following types of astronomical equipment in the order that they became available.

refracting reflecting film photography radio telescope CCD imaging

how to study x-rayy, ultraviolet, and ingrared wavelength

space-based telescopes

quantum efficienccy

the likelihood that a photon falling on the retina will produce a response

intergration time

the time over which the dectector eye can add up photons

Choose all that apply. CCD cameras are better astronomical detectors than the human eye because

they can observe at wavelengths beyond the visible. .their quantum efficiency is higher the integration time can be longer.