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From Wikipedia Commons
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Path of the sun is precisely on the ecliptic,
toward the east, as the months go by
Can you say what occurs in the southern
hemisphere?
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Where does the sun rise and set at various times
of the year?

• generally rises in east and sets in west
• only on equinox days (no matter what latitude)
  are these points due E or W
• maximum (solstice days) sunrise/sunset azimuths
  (for latitude 40º) are shown
• calculating these azimuth angles is complicated
  on ANY day
• for latitude 0º (the equator), the width is 2
  x 23.5º 47º

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Karnak, Egypt looks toward sunset point on
horizon at summer solstice
Bighorn Medicine Wheel, Wyoming spokes point
toward sunrise/sunset points at solstices
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The Sidereal Day and the Solar Day

• Solar Day Time for sun to re-cross your meridian
  24 h 0 min
• Sidereal Day Time for earth to turn once 23 h
  56 min

1 sidereal day 1/4 of the way
1 solar day 1/3 of the way

• if the year were 4 sidereal days long
• it would be 3 solar days long
• there is one more sidereal day than
• solar day in a year
• Astronomers prefer sidereal
• (absolute) time
• sidereal year starts when the sun is at the
  vernal equinox
• local sidereal time is just the hour angle of
  the vernal equinox

start
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Fig.02.17
In one day, the sun drifts 1º toward the east,
along the ecliptic
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Fig.02.24
Sidereal Month Time for moon to revolve once
27.3 day Synodic Month Time for moon to catch up
to sun 29.5 day This last one is the time
between new moon to new moon
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Fig.02.25
Line of nodes the two places where object is ON
ecliptic
If moon is on line of nodes, an eclipse is
possible!!
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What are the Planets? How do they move?

• to naked eye, there are 5 Mercury Venus Mars
  Jupiter Saturn
• all move on ecliptic (almost), usually toward
  the east
• some (inferior) move fast, stay near Sun Mer,
  Ven
• others (superior) move slow, go all the way
  around Mar, Jup, Sat
• all of the heavenly bodies Sun, Moon, 5
  Planets appear to orbit the earth in perfect
  circles, right???
• I mean, really, come on, its obvious that they
  all go around the Earth on perfect circles!!
• so the Earth is the center of everything, right?
• only an idiot would come up with an alternate
  theory

Then explain this!!

• widely varying brightness
• retrograde motion
• plenty of other anomalies

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Fig.02.28
Ordinary motion Of planets, and Sun, and moon,
is EASTWARD along the Ecliptic. Retrograde motion
comes in a variety of patterns
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Mars (superior) goes retrograde occurs near
every opposition
for inferior planets retrograde only occurs every
other opposition!