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48 Cards in this Set

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