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7/31/2019 Lunar Slides
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New 0% Illuminated Waxing Crescent 25% Illuminated on RHS
First Quarter 50% Illuminated on RHS
Waxing Gibbous 75% Illuminated on RHS Full 100% Illuminated
Waning Gibbous 75% Illuminated on LHS
Third (Last) Quarter 50% Illuminated on LHS Waning Crescent 25% Illuminated on LHS
Phases of the Moon
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Rising/Meridian/Setting Times
Phase Rising Meridian SettingNew 6 am Noon 6 pm
Waxing Crescent 9 am 3 pm 9 pm
First Quarter Noon 6 pm MidnightWaxing Crescent 3 pm 9 pm 3 am
Full 6 pm Midnight 6 am
Waning Gibbous 9 pm 3 am 9 amThird Quarter Midnight 6 am Noon
Waning Crescent 3 am 9 am 3 pm
*Assuming the moon is always on the celestial equator and above thehorizon 12 hours per day.
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Lunar Periods
Sidereal Period 27.3 days
The time between successive alignmentsof the earth, moon, and a star
The true orbital period of the moon
Synodic Period 29.5 days
The time between successive alignmentsof the earth, moon, and the sun
The period of the cycle of lunar phases
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Lunar Eclipses
Total Lunar Eclipse The moon is entirely inside the earths umbra
Partial Lunar Eclipse
The moon is partially inside the earthsumbra
Penumbral Lunar Eclipse
The moon is inside the Earths penumbra
These happen regularly and no one notices.The brightness of the moon only decreasesby 10% to 20%
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Solar Eclipses Total Solar Eclipse
The moon completely obscures the sun for anobserver at this location on the Earth
Partial Solar Eclipse
The moon partially obscures the sun for anobserver at this location on the Earth
Annular Solar Eclipse The moon is near apogee and its angular
diameter is insufficient to completely coverthe sun. An observer for whom the moon andsun are aligned will see a ring of the sunaround the moon
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Tides- caused by differential gravitational forces exerted
by the moon (the moon pulls more on one side ofthe earth than the other)- Even though the suns gravitational force is much
larger than the moons, its differential force issmaller (since the size of the earth is small
compared to the earth-sun distance)- This moons differential force causes water bulges
on the earth on both sides of the line to the moon.Tides are caused by the Earths rotation carrying
observers through a water bulge. Thus, typicallyhigh tide occurs twice a day.- Neap Tidesweak tides which occur when the moons
and suns pull are perpendicular- Spring Tides strong tides when the moon and sun are
aligned.