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48 Cards in this Set
- Front
- Back
A named area of the sky
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constellation
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Early device that indicated time and season by casting a shadow.
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gnomon
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Early device that used a scale & a sight on a movable arm to measure a star's position. Also measured latitude.
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quadrant
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Uses only lenses to magnify an image. Refract means to bend light.
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refractor telescope
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the larger light-gathering lens
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objective lens
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the magnifying lens by the eye
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ocular
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The ability of a telescope to bring out details in an image.
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resolution
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The horizontal distance from one wave crest ot the next. In light each color has a different wavelength.
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wavelength
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Two or more lenses made of different kinds of glass mounted together to correct for chromatic aberration. It focuses all of the colors at the same point.
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compound lens
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Uses a mirror to gather light.
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reflector telescope
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Telescope with eyepiece on the side.
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Newtonian reflector
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Telescope with eyepiece on the bottom. It is more compact and easier to use. Problem with diffraction spikes (dark lines) caused by spider.
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Cassegrainian reflector
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Uses a combination of a lenses and mirrors.
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composite telescope
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A composite telescope with a "transparent spider". Popular with amateurs.
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Schmidt-Cassegrainian
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Only radio waves can pass through the atmosphere. Looks like a giant satellite dish.
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radio telescope
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In space above the earth's atmosphere. Primarily a reflector.
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Hubble Space Telescope (HST)
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The astronomical equivalent of latitude and longitude.
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coordinate
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Divides north from south in the sky. It is the plane of the earth's equator projected into the sky.
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celestial equator
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Like latitude in the sky.
Measured in degrees. North = '+' South = '-' |
declination (DEC)
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Like longitude in the sky.
Measured in hours and minutes. One hour = 15 degrees |
right ascension (RA)
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A line passing through the celestial poles and a point called the vernal equinox. Above the prime meridian.
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prime hour circle
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A measure of a star's RELATIVE brightness. The smaller the #, the brighter the star.
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magnitude
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A method of measuring the distance to a star. The wavelengths of the light stretch with increasing distance.
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red shift
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movement across the sky
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proper motion
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movement directly toward or away from us
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radial motion
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The color of a star is the result of its surface temperature. The hottest stars are bluish. The cooler stars are more reddish.
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temperature
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A term used to classify the largest and most luminous stars.
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supergiant
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A very dense, bright star with about the same mass as the sun, but 100 times smaller.
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white dwarf
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The amount of matter contained in a unit.
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density
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Two stars in orbit around each other. Light greatest when side by side. (Variable stars)
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eclipsing binary
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A star that varies in brightness due to regular changes in size. Ex: Delta Cephei with a 4.5 day period.
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Cepheid variable
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Time between the shrinking and growing of a star. How long they go from one bright spurt to the next.
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period
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A white dwarf star that explodes periodically and gets brighter before returning to normal.
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nova
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A destructive explosion of a star.
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supernova
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The small, dense, dark star left over from a supernova.
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neutron star
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A group of related stars that have the same motion.
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star cluster
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Millions of stars that orbit the galaxy's center.
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galaxy
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Visible clouds of dust and gas in space.
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nebula
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QSOs or quasi-stellar objects. Extremely unusual objects that have astronomers puzzled.
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quasar
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An extremely dense object that can trap even light.
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black hole
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"to bend light"
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refract
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What telescope mount is the most common? The altitude is determined by the azimuth. Problem is the it doesn't work for heavy telescopes.
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Altazimuth Mount
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What telescope mount works like a cannon's mount? It can support a heavy telescope. It can lower the telescope to bring ocular closer to viewer. It is a variation of the Altazimuth Mount.
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Dobsonian Mount
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What telescope mount rotates parallel to the earth's equator?
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Equatorial or German Mount
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2 things magnitude depends on
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A star's absolute brightness & the distance of the star from the earth.
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The actual amount of light a star emits.
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absolute brightness
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Star with the larger mass.
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Main Star in an Eclipsing Binary.
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Star with the smaller mass. Usually the brighter star.
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Companion Star in an Eclipsing Binary.
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