Science

Q: The design of modern X-ray telescopes depends on A) lenses made of germanium. B) the prime focus design, with mirrors made of iron. C) grazing incidence optics. D) achromatic lenses to keep the X-rays in focus E) the Cassegrain design, with mirrors made of lead.

Q: One advantage of the Hubble Space telescope over ground based ones is that A) it is larger than any Earth-based telescopes. B) it can better focus X-ray images. C) it can make better observations of the ozone layer. D) its adaptive optics controls atmospheric blurring better. E) in orbit, it can operate close to its diffraction limit at visible wavelengths.

Q: Compared to optical telescopes, radio telescopes are built large because A) they're less expensive to make than optical telescopes. B) radio waves have very long wavelengths. C) atmospheric turbulence is more of a problem. D) radio sources are harder to find. E) radio waves are absorbed by the atmosphere.

Q: In astronomy, an interferometer can be used to A) yield better seeing conditions with optical telescopes. B) decrease the effects of light pollution in getting darker sky backgrounds. C) improve the angular resolution of radio telescopes. D) increase the sensitivity of infrared telescopes to longer wavelengths. E) speed up the processing of CCD images.

Q: The Arecibo radio telescope is laid out like which optical telescope design? A) prime focus reflector B) Newtonian reflector C) Cassegrain reflector D) Coude reflector E) grazing incidence reflector

Q: What is true of radio telescopes? A) They have poorer angular resolution than a refractor of the same size. B) They have better angular resolution than a reflector. C) They are the smallest, most compact telescopes. D) They can only be used above the atmosphere. E) They are most sensitive to the opacity of the ozone layer.

Q: What problem does adaptive optics correct? A) defects in the optics of the telescope, such as the original Hubble mirror B) the opacity of the Earth's atmosphere to some wavelengths of light C) the light pollution of urban areas D) turbulence in the Earth's atmosphere that creates twinkling E) chromatic aberration due to use of only a single lens objective

Q: Green light has a shorter wavelength than orange light. In a 5 inch telescope, green light will A) provide better angular resolution than orange light. B) come to the same exact focus as orange light. C) provide worse angular resolution than orange light. D) allow dimmer stars to be observed. E) reduce the effects of atmospheric turbulence.

Q: What is the light-gathering power of an 8 inch telescope compared to a 4 inch telescope? A) 2 times better B) 4 times better C) 8 times better D) 16 times better E) 32 times better

Q: Compared to a 5 inch prime focus reflector, a 5 inch Newtonian reflector will A) have more light gathering power. B) have the same light gathering power. C) be easier to build. D) have more chromatic aberration. E) have a larger hole in the center of its mirror.

Q: What is the resolution of a telescope? A) its ability to see very faint objects B) its ability to distinguish two adjacent objects close together in the sky C) its ability to make distant objects appear much closer to us D) its ability to separate light into its component colors for analysis E) its ability to focus more than just visible light for imaging

Q: The amount of diffraction and thus the resolution of the telescope depends upon A) the wavelength used and the size of the main telescope objective lens or mirror. B) the design of the telescope. C) whether the telescope is a reflector or refractor. D) the brightness of the object. E) the size and sensitivity of the CCD chip used for imaging.

Q: The angular resolution of an 8 inch diameter telescope is ________ times greater than that of a 2 inch diameter telescope. A) 2 B) 4 C) 8 D) 9 E) 16

Q: It is diffraction that limits the ________ of a telescope of a given objective diameter. A) magnification B) light grasp C) resolution D) aperture E) interference

Q: Adding a secondary concave lens of carefully chosen different glass to the primary lens on a refractor allows A) chromatic aberration to be reduced. B) X-rays to be focused. C) effects of atmospheric turbulence to be reduced. D) greater magnification. E) more light to be gathered.

Q: A major advantage of a Newtonian reflector over a refractor is A) its compact size. B) the elimination of chromatic aberration. C) there are only two lenses to grind. D) the central hole in the mirror is smaller. E) the elimination of the secondary mirror.

Q: The primary purpose of a telescope is to A) collect a large amount of light and bring it into focus. B) magnify distant objects. C) separate light into its component wavelengths. D) make distant objects appear nearby. E) measure the brightness of stars very accurately.

Q: The most important advantage of CCDs over film is that A) they record much more light in a given exposure time. B) their images do not have to be developed as film does. C) they record colors better than film can. D) they can cover larger areas of the sky than film can. E) their images never fade, as film can.

Q: What problem do refractor telescopes have that reflectors don't? A) diffraction limited resolution B) light loss from secondary elements C) chromatic aberration D) atmospheric blurring E) bad seeing

Q: Which of the following is NOT a reason to use a reflecting telescope rather than a refractor? A) Lenses are subject to chromatic aberration. B) Lenses are harder to focus than mirrors. C) Lenses absorb light, while mirrors do not. D) Heavy lenses, which can only be supported at their edges, tend to deform under their own weight. E) A lens must have two precision surfaces; a mirror needs only one.

Q: Which type of telescope has the simplest light path? A) prime focus reflector B) single lens refractor C) achromatic refractor D) Newtonian reflector E) Cassegrain reflector

Q: Galaxies look the same whether viewed in visible or X-ray wavelengths.

Q: The Compton GRO was the first telescope used for our exploration of high-energy astronomy.

Q: The mirrors for X-ray telescopes are the same shape as those of optical reflectors.

Q: Due to our ozone layer, ultraviolet astronomy must be done from space.

Q: Like radio and optical astronomy, infrared astronomy is easily done with ground-based telescopes.

Q: Radio astronomy can only be done from up in space, due to our ionosphere.

Q: Optical interferometry is more in use than radio interferometry.

Q: The Earth's atmosphere is the major factor limiting the use of ground-based radio telescopes.

Q: Optical telescopes are usually used only at night, but radio telescopes can be used day or night.

Q: In the future, adaptive optics will greatly enhance the resolution of the Hubble Space Telescope.

Q: The opacity of the atmosphere is partially corrected via adaptive optics.

Q: Stars do not twinkle; the instability of the atmosphere causes this effect.

Q: All modern large optical telescopes are refractors.

Q: Radio telescopes have poorer angular resolution than optical telescopes because radio waves have a much longer wavelength than optical waves.

Q: The 400" Keck reflector can see objects 100 times fainter than the 40" Yerkes lens.

Q: A telescope with an 8-inch mirror will collect twice as much light as one with a 4-inch mirror.

Q: Mt. Palomar's 200" Hale telescope is the largest reflector now in service.

Q: The light-gathering ability of a telescope is most dependent on the diameter of its primary objective.

Q: Photography with film is still the preferred way of capturing fine detail in the faintest, most distant galaxies.

Q: The Cassegrain reflector needs a primary concave main mirror and a smaller, convex secondary mirror to reflect light back through a hole in the primary.

Q: The Hubble Space Telescope gives us its best resolution with X-rays.

Q: A Newtonian reflector needs no secondary mirror.

Q: CCD detectors gather light 10-20 times faster than the most sensitive photographic film.

Q: A telescope design that uses a lens and no mirrors is a refractor.

Q: All optical telescopes will bring the light from a star to a focus.

Q: Chromatic aberration affects reflector telescopes.

Q: Galileo is credited with designing the first reflector telescope.

Q: The simplest reflector telescope design is the prime focus reflector.

Q: When an electron moves from a lower to a higher energy state, a photon is ________.

Q: The common element discovered in the Sun's spectrum before it was found here is ________.

Q: The common element with bright red, blue-green, and violet emission lines is ________.

Q: Fraunhofer was the German astronomer who first noted ________ lines in the Sun's spectrum.

Q: A dense, hot body will give off a(n) ________ spectrum.

Q: Stefan's law notes that total energy radiated is proportional to the ________ power of the temperature of the blackbody.

Q: Knowing the peak emission wavelength of a blackbody allows you to determine its ________.

Q: The Sun's blackbody curve peaks in the ________ portion of the spectrum.

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