AM: anti-meridian
PM: Post-meridian
solar noon: the highest point the sun is in the sky
longitude: angle measured from prime meridian
-east to west
latitude: angle from equator
-north to south
circumpolar: objects near the north pole that never seem to set
Diapositiva 2
Constellation- one of 88 sectors of the sky
asterism - star pattern within a constellation
ecliptic - path sun takes around celestial sphere
declination - angular distance of a point North or South of the celestial equator
right ascension - the distance of a point measured by the East of the First Point of Aries, measured along the celestial equator and expressed in hours, minutes, and seconds.
celestial equator - the projection into space of the earth's equator, equidistant from the celestial poles
equator - great circle constituting of the parallel 0 degrees, dividing the earth into hemispheres
First Point of Aries: vernal equinox
Diapositiva 3
*the sky rotates opposite of the celestial poles
*rises on east, sets in west
-The star Polaris is also known as the fastener of the sky
*earth rotates counterclockwise
*planet means "wanderer" in Greek
*halfway b/w the poles, 90 degrees, is the celestial equator
Things to Note
Diapositiva 4
Declination and Right Ascension
Declination is measured just the same as latitude (from the equator)
North: positive values South: negative values
Right Ascension is similar to longitude, but counted from the "vernal equinox" , where the ecliptic crosses the celestial equator.
360 degrees = 24 hours
15 degrees = 1 hour
Diapositiva 5
Seasons
*become more pronounced the further N or S one travels from the equator
Seasons are not caused by the distance earth is from the sun, but rather by the degree of the earth's axis tilt (23.5 degrees.)
The vernal and autumnal equinoxes deliver equal amounts of sunlight across the globe
The North leans in toward the sun during the summer solstice, and away during the winter solstice
The South leans in toward the sun during the winter solstice, and away during the summer solstice
The angle determines the intensity/where the earth receives the most sunlight (heating distribution)
During the summer, The north receives the most hours of sunlight
During the equinoxes, the both hemispheres receive equal hourly amounts of sunlight
During the winter, the South receives the most hours of sunlight