A very neat target for skywatchers is our nearest celestial neighbor, the moon. Easily visible in the night sky, it is a great target for naked eyes, binoculars, and telescopes of all sizes. Located a mere 250,000 miles from Earth, it is a target rich in terrain features just ripe for the viewing!
When viewing the moon, the features that jump out at you are the lunar mare, or “seas”. They’re the large dark spots on the face of the moon. Named in antiquity, ancient astronomers believed that they were large bodies of water. With the invention of the telescope, that was disproved quickly as craters, mountains, and other features can be discerned within these “seas”.
A map of the moon lists the names of these “seas”, formed early in the history of the solar system during a period known as the Late Heavy Bombardment. They were formed by large impacts which filled in with molten lava. They form the facial features of “the man in the moon”. The names are in Latin. The most prominent of these seas are Mare Imbrium (Sea of Showers), Mare Serenitatis (Sea of Serenity), and Mare Nubium (Sea of Clouds). These three mare make up the two eyes and mouth of the man in the moon, respectively. Below and to the right of the moon face’s right eye is Mare Tranquillitatis (Sea of Tranquility), which is the site of the first manned moon landing. Mare Nectaris (Sea of Nectar) is located below the Sea of Tranquility and Mare Foecunditatis (Sea of Fertility) is to the right and slightly below Tranquility. On the far right upper-edge of the moon lies Mare Crisium (Sea of Crises) To the far left of the moon lies the large region named Oceanus Procellarium (Ocean of Storms). As a bonus, all of these regions are visible with the naked eye, so be sure to look for them!
When using binoculars, larger moon craters can be spotted. The most prominent of these is Tycho. Located in the moon’s southern hemisphere, it is the huge crater with rays spewing forth. Obviously the site of an ancient impact, the center of the crater appears to be raised as if you dropped a pebble into the water. The massive craters Aristarchus, Kepler, and Copernicus are also visible on the left-central portion of the moon. These craters are named after some of the forerunners of modern astronomy. See if you can spot them!
The best time to view the moon with a telescope is during the phases, not when the moon is full. The shadow along the moon’s terminator (day/night border) is the best place to see features in detail, as the shadows help bring definition to the features of the moon. The poles, particularly the south pole of the moon, also have a great deal of features. There is a giant basin at the south pole, called the South Pole-Aitken Basin that is partially visible, as well as scores of craters. The South Pole-Aitken Basin is one of the deepest impact craters in the solar system at approximately 8 miles deep! The Lunar Appenine mountain range in between the “eyes” is another treat to view with a telescope. The edges of the seas are also interesting, as you can see the drop-offs from the surrounding lunar surface
After you’ve mastered the lunar surface and spotted the various terrain features, try finding the Apollo landing sites! No matter which telescope or which magnification you use, you won’t be able to see the actual landing sites or the artifacts left behind by those who undertook the boldest voyage in the history of human exploration. However, you will be able to see the regions that the astronauts saw on their landing approach, and the type of terrain that the astronauts would have dealt with as they bounced across the surface. There were nine manned moon-bound missions, but only six of these made landings. Apollos 11, 12, 14, 15, 16, and 17 made landings. Apollo 8 was the first mission to orbit the moon, Apollo 10 was a test of the Lunar Module in the vicinity of the moon, and Apollo 13 suffered an accident that warranted a quick return to Earth and so skipped the landing phase of the mission.
One may think that only 50% of the lunar surface is visible from Earth, since the tidally-locked nature of the moon keeps only one side of the moon facing Earth. In fact, because of a slight wobble, called libration, up to 60-65% of the moon is visible from Earth over the months. So, where it’s true that 50% of the surface of the moon is visible at any given time, if you photographed each of the full moons of the year, you can see part of the far side as well, albeit just a small portion!
Our neighbor, the moon, is a very intriguing object to view in the night sky. It’s bright, visible all year from anywhere on Earth, and is full of features for any level of viewing. It’s a great first target for that new telescope, or that new pair of binoculars. So, if you find yourself looking to visually explore strange, new worlds, look no further than our dear moon!
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