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.