If this is your first time looking at the Moon through a telescope, you may feel the same wonder Galileo felt seeing that familiar orb in the sky transform into another world. You’ll see valleys, and the cracks in the Moon’s surface called rilles, formed when the lava that once filled a basin cooled and contracted. Now you’ll see real mountains, and not just craters but the crater chains created when impact debris splashes around the main craters. Under the gaze of a telescope, the Moon becomes too big to take in at once.
Image contributed by Flickr user rjcavallini2009. Observing the Moon with a telescope in Maranhão, Brazil. Pick up a pair of binoculars, and the Moon transforms. You may even be able to see some of the bright streaks that are ray systems emanating from the Copernicus or Tycho craters, created when material was thrown outward by the force of the original impacts. You may be able to see some of the larger impact craters on the Moon’s surface if your vision is sharp enough, including Copernicus, Kepler, and Aristarchus and Tycho. Give yourself plenty of time for your eyes to adjust and look carefully. What you see on the Moon with your eyes only will vary depending on your eyesight. The lighter-colored areas are called the highlands, and show the earliest crust on the Moon, dominated by a type of rock called anorthosite, which is primarily made up of the white mineral anorthite or plagioclase. We call these areas the lunar seas, or maria. The lava was similar to the basalt that erupts on Earth and, like on Earth, cooled to form a relatively dark-colored rock. Because the impact basins were often the lowest places on the Moon’s surface, they would begin to fill with erupting lava. These dark areas formed when massive asteroid or meteorite impacts on the Moon’s surface created basins. In the Moon’s youth, its interior was still molten, and magma would erupt onto its surface. These gray patches are solidified volcanic lava flows. Looking at the Moon with only your eyes, you see mostly areas of white and gray. The shadows on the surface will be more pronounced, and help distinguish features you might otherwise miss.
ON EARTH I AM DEAD I LIVE ON THE MOON FULL
You can look at the Moon during any of its illuminated phases, but for better viewing of craters and mountains, try phases other than the full Moon. During its crescent phase in the twilight or dawn, you can also sometimes see the dark portion of the Moon glowing faintly in the sunlight that reflects off Earth, an effect called earthshine. The Moon has no glow of its own, but shines with the reflected light of the Sun. Credit: NASA/GSFC/Arizona State University The near side of the Moon, as seen by the cameras aboard NASA's Lunar Reconnaissance Orbiter spacecraft.