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Hour Test 2
Cards
29
Astronomy
Undergraduate 3
10/11/2012

Additional Astronomy Flashcards

 


 

Cards

Term
Constellations
Definition
one of 88 areas into which the sky has been divided for convenience in referring to the stars or other objects therin
Term
celestial sphere
Definition
the hypothetical sphere centered at the center of the earth to which it appears that he stars are affixed
Term
right ascension
Definition
Celestial longitude, measured eastward along the celestial equator in hours of time from the vernal equinox
Term
declination
Definition
Celestial latitude, measured in degrees north or south of the celestial equator
Term
celestial equator
Definition
the intersection of the celestial sphere with the axis of rotation of the Earth
Term
celestial poles
Definition
the intersection of the celestial sphere with the axix of the rotation of the earth
Term
vernal equinox
Definition
the equinox crossed by the sun as it moves to northern decliations
Term
Autumnal equinox
Definition
of the two locations in the sky where the ecliptic crosses the celestial equator, the one that the sun passes each year when moving from northern to southern declinations
Term
sidereal day
Definition
a day with respect to the stars
Term
solar day
Definition
a full rotation with respect to the sun
Term
Gregorian calendar
Definition
the calendar in current use, with normal years that are 365 days long, with leap years every 4th year except for years that are divisible by 100 but not by 400
Term
pole star
Definition
a star approximately at a celestial pole; Polaris is now the pole star; there is no south pole star.
Term
Umbra
Definition
Of a sunspot, the dark central region; (b) of an eclipse shadow, the part from which the sun cannot be seen at all.
Term
Penumbra
Definition
For an eclipse, the part of the shadow from which the sun is only partially occulted; (b) of a sunspot, the outer region, not as dark as the umbra.
Term
Bailey's Beads
Definition
Beads of light visible around the rim of the moon at the beginning and end of a total solar eclipse. They result from the solar photosphere shining through valleys at the edge of the moon.
Term
Diamond Ring Effect
Definition
The last bailey’s bead glowing brightly at the beginning of the total phase of a solar eclipse, or its counterpart at the end of totality.
Term
annular eclipse
Definition
A solar eclipse at which the moon is too small in angular size to cover the solar photosphere, leaving a ring (annulus) of bright photosphere showing. Annular eclipses are visible at about the same rate as total solar eclipses: about every 18 months. The corona is not visible at annular eclipses, because too much bright photosphere remains.
Term
revolution
Definition
the orbiting of one body around another
Term
rotation
Definition
Spin on an axis
Term
ecliptic plane
Definition
the plane of the earth's orbit around the sun
Term
retrograde rotation
Definition
the rotation of a moon or planet opposite to the dominant direction in which the sun rotates and the planets orbit and rotate
Term
Spring tides
Definition
the tides at their highest, when the Earth, moon and sun are in a line (from "to spring up")
Term
Neap tides
Definition
the tides when the gravitational pulls of sun and moon are perpendicular, making them relatively low
Term
Troposphere
Definition
the lowest level of atmosphere of the Earth and some other planets, in which all weather takes place
Term
Aurora borealis
Definition
the Northern aurora
Term
Aurora australis
Definition
The Southern aurora
Term
Mare
Definition
One of the smooth areas on the moon or on some of the planets
Term
Rilles
Definition
sinuous depressions on the lunar surface, apparently volcanic, perhaps huge collapsed lava tubes or lava channels
Term
Terminator
Definition
the line between night and day on a moon or planet; the edge of the part that is lighted by the sun
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