Page 14 - Curriculum Visions Dynamic Book

 The stages of a lunar eclipse.
annUlar Ringlike.
apogee The point on an orbit where the orbiting object is at its farthest from the object it is orbiting.
corona (pl. coronae) A coloured circle seen around a bright object such as a star.
eclipse The time when light is cut off by a body coming between the observer and the source of the illumination (for example, eclipse of the Sun), or when the body the observer is on comes between the source of illumination and another body (for example, eclipse of the Moon).
lUnar Anything to do with the Moon. penUmbra A region that is in
semidarkness during an eclipse.
perigee The point on an orbit where the orbiting object is as close as it ever comes to the object it is orbiting.
saros cycle The interval of 18 years 111/3 days needed for the Earth, Sun, and Moon to come back into the same relative positions. It controls the pattern of eclipses.
solar Anything to do with the Sun.
total eclipse When one body (such as the Moon or Earth) completely obscures the light source from another body (such as the Earth or Moon).
Umbra A region that is in complete darkness during an eclipse.
Eclipses
An eclipse occurs when three bodies happen to line up,
and one body blocks out the light from another. But the Moon is barely big enough to block out the Sun (and cause a total eclipse) when it is at its closest (perigee). When the Earth is farthest from the Moon (apogee), a total eclipse does not occur. Part of the Sun is always visible as the Moon moves between the Sun and the Earth. This is called an annUlar eclipse.
Both solar and lUnar eclipses occur in groups separated by about 18.6 years. This interval is called the Saros cycle.
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