Studied by 1 personTags & Description
Rotation
the spin of an object around an internal axis
Horizon
the horizontal circle defining the lower edge of the sky
altitude
the angular distance from a point on the sky to the point on the horizon directly below it
latitude
a measure of location specifying north-south position on earth running from 0 degrees to the equator @ 90 degrees north & 90 degrees south
Longtitude
a measure of location specifying east-west position on earth
angular size
angular distance measured on a sphere in degrees, minutes, arcminutes, and arcseconds
celestial sphere
an imaginary transparent sphere surrounding earth, on which positions of the stars, planets, and other celestial bodies are projected from extensions of earth's coordinate system
celestial equator
the extension of earth's equator onto the celestial sphere
Polaris
the star that is found very near earth's celestial pole
north celestial pole
the extension of earth's north pole on the celestial sphere
south celestial pole
the extension of earth's south pole on the celestial sphere
zenith
the point on the sky directly overhead from the observer
meridian
a circular arc crossing the celestial sphere and passing through the local zenith and celestial pole
declination
the position of an object on the celestial sphere, measured similarly to the latitude on earth
sidereal day
the time taken by the earth to rotate on its axis relative to the stars
solar day
the time between successive crossings of the same meridian on the sky by the sun
small angle formula
a mathematical relationship between the angular size of an object, as measured on the sky, and the object's distance and physical size
analemma
the figure-8 pattern formed by charting the daily position of the sun @ the same time of the day over the course of 1 year
summer solstice
the day (june 21st) with the most hours of sunlight, when the sun appears highest in the sky
winter solstice
the day (december 21st) with the fewest hours of daylight, when the sun appears lowest in the sky
equinox
A day when the hours of daylight and darkness are equal
orbit
the cyclical path in space that one object makes around another object
axial tilt or obliquity
the angle between a planet's rotation axis and a line perpendicular to the planet's orbital plane
precession
the rotation of a planet's spin axis, similar to that of a wobbling toy
constellations
a group of stars that form a pattern, and the designated region of the sky surrounding them
circumpolar constellation
a constellation that, from the viewer's perspective, never rises or sets.
ecliptic
the path that the sun appears to follow against the background as defined by earth's orbit around the sun
zodiac
13 constellations that lie close to the plane of the ecliptic
phase (of the moon)
as seen by observation of the earth, the appearance of the illuminated portion of the moon, which change cyclically so the moon orbits the earth
scientific model
an idea or set of ideas used to create testable explanations
New moon
moon is between earth and the sun lunar face illuminated points away from the earth
waxing crescent
appears in the late afternoon sky as sun sinks in the west
first quarter moon
moon at its highest altitude @ sunset occurs seven days after new moon
waxing gibbous
after first quarter
full moon
the time when the Moon is fully illuminated 7 days after first quarter highest point in the night sky @ 12
waning gibbous
appears on eastern horizon closer to midnight
third quarter
7 days after full moon rises @ midnight
waning crescent
last phase before it starts back over
synodic month
the amount of time it takes the moon to cycle through its phases (29.5 days)
sidereal month
the amount of time it takes the moon to make a complete orbit
Eclipse
the passing of one celestial body through the shadow of another
penumbra
the outer region of a shadow cast by an extended object
umbra
the inner region of a shadow cast by an extended object
Total lunar eclipse
an eclipse that occurs when the moon passes through Earth's umbral shadow
partial lunar eclipse
an eclipse that occurs when the moon passes partially through the earth's umbral shadow
total solar eclipse
an eclipse that occurs when a region of earth's surface passes under the moon's umbral shadow and the sun disk is fully blocked
totality
the moment or duration of total concealment of the sun or moon during an eclipse
apogee
the distance of farthest approach of an object orbiting earth
perigee
the distance of closest approach of an object orbiting earth
aphelion
the distance of farthest approach of an object orbiting the sun
perihelion
the distance of closest approach of an object orbiting the sun
annular eclipse
a solar eclipse that occurs when the positions of the moon and sun are such that the lunar disk does not fully block out the solar disk
partial solar eclipse
an eclipse that occurs when a region of earth's surface passes under the moon's penumbral shadow
line of nods
the line defined by the intersection of the moon's orbital plane and earth's orbital plane around the sun.
mythology
a collection of stories used to explain phenomena whose physical basis is not understood
megalith
a large stone used as a monument or part of a monument
paleolithic period
the period extending from 2.6 million years to 10,000 years ago (earliest known use of stone tools)
neolithic period
the period extending from 10,000 BCE to between 4500 and 2000 BCE, when farming was introduced
geocentric model
a model stating that earth is the body around which all other solar system objects orbit
heliocentric model
a model stating that the Sun is the body around which all other solar system objects orbit
parallax
a displacement or difference in the apparent position of an object viewed along two different lines of sight
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