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Astronomy Exam Review Notes

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Natural Science
NATS 1745
Robin Metcalfe

Zeinath is a point above youThe Suns Daily Cycle1Due to Earths 24hour eastward spin around its polar axis the sun moves westward across the skyit rises in the east reaches its highest point at noon then sets in the west Picture2NHemisphere Sun is mostly seen on the south side of the sky reaching due south at noon3SHemisphere sun is mostly seen on north side of sky reaching due north at noon pictureLocal noon when ur location is facing the sunLocal midnight When your location is facing the opposite side of the sky from the sunlocal sunrise sunset when the suns direction is perpendicular to your location Suns annual cycle1fall and spring equinnox Sep23mar 21 Sun rises due E and sets due W speeding equal time above and below the horizonequal day and night0 equinx Latin for equal nightpictureWinter solstice Sun rises and sets at its southernmost position traversing a short low are in the skyshortest day of the year and lowest noon sunThe seasonal changes in the suns daily are due to Earths 235degree tilt from its orbit around the sun Winter When a hemisphere is tilted away from the sun sunlight hits indirectly causing low arcs and less light per areaSummer when a hemisphere is tilted toward the sun sunlight hits more directly causing high areas and more light per areaDecember 22 winter solstice March 21 vernail equinx june 22 summer solstice september 23 when one hemisphere is tilted towards the sun the other is tilted away there fore the seasons are longer during one side then the otherat 235 N degres the sun can be seen directly overheadat 235N the noon sun is in the cancer constellation looks like a crab235S The noon sun is in the Capricorn constellation when it is directly overheadthe lower your latitude the higher the suns daily pathSuns daily path is steeper at low latitudes the sun rise and sets fasterLow latitudes are warmer because they recieve more light thro out the yearwithin 235 degrees summer solstice doesnt set and winter solstice doesnt risethe higher the latitude the more consecutive polar daysnightPositional Astronomy and the Cycle of the StarsThe Celestial Sphere our view of the sky projected on to the surface of an imaginary sphere a visual tool for describing the positions of celestial bodies North celestial pole is a line from the north pole going straight to the North celestial sphere same goes for south and equatorZeinath is a point above you Mayan AstronomyMayan sites and records reveal the Maya tracked celestial cycles in order to worship the mayan gods associated with celestial bodies1 Pyramid of Kukulcane365 steps shows mayan we aware of the suns annual cycleannual serpentpattern of light and shade tracks the time of yearfull serpent ends at kulkulcans head2 El caracole openings in the observatory doen are aligned to the NmostSmost setting positions of planet Venus allowed the maya to measure the duration of venus full path in the sky3 Mayan bark books durable boooks contained listings of historical events including celestial eventsDersend codex contains mayan dates of the full eclipse cyclethe Venus cycle4 2012 Mayan Calendar notation ends on december 212012 This is not based on any astronomical cycle Mayan records describe this date as the last date of one calendar cycleas opposed to the last date of all time5 Mayan number symbols visually represent their quantity making them effiecent for addition and subtraction of large numbers This allowed the Mayan to easily record theof days between celestial events and to recognize their longterm patterns6 EclipseBelieved by many civilizations to be hearlds of bad times due to the damaged apperance of the sun or monTheir longterm complex cycle led may to believe that eclipse are random The maya however found their patternThe Moons Phases1 Lunation one complete cycle of moon phase 2953 days2As the moon orbits Earth once a month earth sees different portions of its sunlit side causing the moons appearance to cycle from completely dark New to completely illuminated Full3When the moon is waningfrom full to new its lit on the left when the moon is waxingfrom new to full its lit on the right4The larger the visible portion of the moons lit side the more night hours the moon is visibleFull moon is only seen at nightEclipses1 A solar eclipse occurs when the moon New passes between Earth andSun and casts its shadow on EarthA total eclipse is seen from the parts of Earth in the Moons primary shadowumbraa partial eclipse is seen from the parts of earth in the moons secondary shadowpenumbra
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