The telescopic Moon
Galileo's published observations revealed mountains, pits and an uneven lunar surface, helping to transform the Moon from a perfect celestial disk into another world.
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Watch the Moon sweep closer to Earth at perigee and farther away at apogee, with each full moon placed on the same curve.
Lower points are closer to Earth. Gold markers show full moons; a red-ringed marker identifies a calculated supermoon.
The Moon does not travel around Earth in a perfect circle. Its elliptical orbit brings it to a nearest point called perigee and a farthest point called apogee during each orbit.
NASA gives typical distances of about 363,300 km at perigee and 405,500 km at apogee, while stressing that the exact extremes vary. A full moon near perigee is popularly called a supermoon; it is not a formal astronomical classification.
Here, a full moon is highlighted as “super” when it lies within the closest 10% of that month's calculated distance range—the commonly used 90%-of-perigee convention.
Galileo's published observations revealed mountains, pits and an uneven lunar surface, helping to transform the Moon from a perfect celestial disk into another world.
Apollo 11 placed a laser retroreflector on the surface. Observatories could time returning laser pulses and measure the Earth–Moon separation directly.
Modern lunar laser-ranging archives span more than fifty years and help researchers study the Moon's orbit, rotation and tests of gravity.
Background: NASA: Supermoons, NASA: Galileo's observations, and NASA lunar laser-ranging data. Chart values are ChronoWaves estimates for general exploration, not navigation.