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Solar and Lunar EclipsesSpica Occultation

Solar Eclipse of 585BC

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Famous Eclipse

A famous solar eclipse took place on {-584,5,22} in the Gregorian calendar. This is the same as May 28, 585BC in the Julian calendar.

The philosopher Thales, born in Miletus in Turkey sometime before 600BC, is supposed to have predicted this eclipse many years in advance. (Presumably he used the 19-year eclipse cycle to make the prediction.)

On the day of the eclipse the Medes and the Lydians, about to commence battle, make peace after witnessing the total solar eclipse and taking it as an omen (or so the story goes).

maxd=SolarEclipse[{-584,5,1}]

EclipseTrackPlot[maxd];1;

We see that the shadow of the Moon, at maximum eclipse, is over the Atlantic ocean.

MoonShadow[maxd]

But let us set our site location to a place in Asia Minor.

SetLocation[{GeoLongitudeRule30 Degree,
GeoLatitudeRule40 Degree,
TimeZoneRule2}];

The Moon's shadow now passes over that location at the following time.

d={-584,5,22,17,23,20};

MoonShadow[d]

From the above we see that the duration of the total eclipse is 4 minutes.

At the given time and place, the Sun and Moon are 0.02 degrees apart.

Separation[Sun, Moon, d,
ViewPointRuleTopoCentric]

The Sun and Moon are 18 degrees above the local horizon.

HorizonCoordinates[Moon, d,
ViewPointRuleTopoCentric]

And all this happens about 100 minutes before sunset.

SunSet[d]

The *partial* phase of the eclipse begins at {-584,5,22,16,22,57}.

d1=EclipseBegin[Sun,Moon,TopoCentric,d]

The *partial* phase of the eclipse ends at {-584,5,22,18,20,22}.

d2=EclipseEnd[Sun,Moon,TopoCentric,d]

The Moon first begins to cover the bottom (and slightly right) side of the Sun.

PlanetPlot3D[Sun,{-584,5,22,16,22+10,57},
ViewPointRuleTopoCentric,
ViewVerticalRuleZenith];1;

At mid-eclipse the Sun is *totally* covered by the Moon.

PlanetPlot3D[Sun,{-584,5,22,17,23,20},
ViewPointRuleTopoCentric,
ViewVerticalRuleZenith];1;

The Moon finally ends by leaving the top (and slightly left) side of the Sun.

PlanetPlot3D[Sun,{-584,5,22,18,20-10,22},
ViewPointRuleTopoCentric,
ViewVerticalRuleZenith];1;

At the beginning of the partial phase, the penumbral shadow just starts to touch the site location.

PlanetPlot[Earth, d1,
EpilogRule{RGBColor[1,0,0],
LocationRing[15 Degree],
RGBColor[0,1,0],
LocationRing[ 1 Degree]}];

At mid-eclipse, the umbral shadow covers the site location.

PlanetPlot[Earth, d,
EpilogRule{RGBColor[1,0,0],
LocationRing[15 Degree],
RGBColor[0,1,0],
LocationRing[ 1 Degree]}];

At the end of the partial phase, the penumbral shadow again just touches the site location.

PlanetPlot[Earth, d2,
EpilogRule{RGBColor[1,0,0],
LocationRing[15 Degree],
RGBColor[0,1,0],
LocationRing[1 Degree]}];

Solar and Lunar EclipsesSpica Occultation



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