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Eclipse PredictingMoonShadow, SolarEclipse, EarthShadow, LunarEclipse

6.1 The EclipseTrackPlot Function

EclipseTrackPlot is useful for displaying details of the umbra and penumbra regions of either a solar or lunar eclipse. It can also be used to display tracks of occultations of stars or planets by the Moon.

Plotting the track of a solar or lunar eclipse.

In the graphic that is returned by EclipseTrackPlot, the gray area is the region that experiences a partial eclipse at some point during the eclipse. The upper and lower red lines represent the edges of the partial eclipse shadow, and the green lines at the end represent the edges where the partial eclipse ceases because of either sunrise or sunset.

Here you see the track of the total solar eclipse of 1948 November 1.

In[3]:=EclipseTrackPlot[SolarEclipse[{1948,11,1}]];

A solar eclipse is only visible from a small portion of the Earth, perhaps a band 100km across, indicated with the black line.

Lunar Eclipses

A lunar eclipse is visible from half the Earth. You can view the eclipse from any point on the side of the Earth facing the Moon at the time it is occurring.

The lunar eclipse of June 1993 is total for 96 minutes and begins at 23:11 local time in Melbourne.

In[4]:=EclipseTrackPlot[LunarEclipse[{1993,6,5}]];

In the graphic, the Moon is the small circle in the center, and over time it sweeps across the band from right to left. The two bigger disks represent the fixed umbra and penumbra shadows of the Earth.

Lunar Occultations

EclipseTrackPlot can also be used to find the regions on Earth in which you can see an occultation of a star or a planet by the Moon. A solar eclipse is also an occultation of the Sun by the Moon.

Plotting the track of a lunar occultation on the surface of the Earth.

On 1995 January 23, there is an occultation of the star Spica by the Moon, but it is visible only from North America. This is a track of the precise region from which the occultation is visible.

In[5]:=EclipseTrackPlot[Earth, Moon, Spica,
{1995,1,23,11+11,0,0}];

As with PlanetPlot, you can use the option PlotRange to zoom into a smaller part of the surface of the Earth. The default is PlotRange -> {{-180, 180}, {-90, 90}}, which shows the entire surface.

Note that you can use the function EclipseBegin to determine when the star Spica or any other star is eclipsed by the Moon.

Eclipse PredictingMoonShadow, SolarEclipse, EarthShadow, LunarEclipse



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