Kitt Peak Nightly Observing Program
Splendors of the Universe on YOUR Night!
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Aristarchus and Herodotus
Aristarchus is not a particularly large crater, but it manages to stand out as an extremely bright crater. Near the northwestern limb of the Moon, Aristarchus is more reflective than the darker Oceanus Procellarum surrounding it. Nearby crater Herodotus is similar in size, but different in appearance. Herodotus is shallower and darker.
Copernicus is a large, conspicuous crater located in the Oceanus Procellarum (Ocean of Storms). It has extensive rays of ejecta spanning hundreds of kilometers from the rim of the crater. This crater is likely to be only hundreds of millions of years old—young for a lunar crater.
Because of its very smooth, dark floor, Plato is a very distinct crater, seen just north of Mare Imbrium. Plato is 101 km across, and the peaks of the rim rise 2,000 meters above the floor.
Apollo 15 landed in the Hadley plains, near Hadley Rille. This mission was the first long, more science-focused lunar landing mission. During this mission, a Lunar Roving Vehicle was used for the first time. One of the most exciting findings of Apollo 15 was a 4.1 billion year old rock, known now as the Genesis Rock. This is also the mission during which the famous hammer and feather experiment was conducted. Astronaut David Scott dropped a feather and hammer at the same time, demonstrating that objects fall at the same rate regardless of their mass. While air resistance on Earth would slow the feather down, the feather hit the ground at the same time as the hammer on the Moon. Though we cannot see anything left behind by the astronauts form Earth, the Lunar Reconnaissance Orbiter can see some of the items left behind at the landing site from orbit of the Moon.
The Mare Imbrium Impact Basin formed when a large object crashed into the Moon 3.9 billion years ago. subsurface lava rose to flood the giant crater, eventually solidifying into a younger, smoother terrain. Prominent features of Mare Imbrium include the crater Plato to the north, with a dark crater floor; Sinus Iridum (meaning Bay of Rainbows) to the northwest, with the Montes Jura mountain range forming a distinct C-shaped knob on the edge of the mare; and the 3 mountain ranges—Montes Alpes, Caucasus, and Apenninus—that mark the eastern edge of the mare.
Also known as a twilight zone, a terminator is where the shadow of night and the light of day come to meet on a planetary body. At the edge of where the Sun’s light reaches, the terminator is constantly moving as the Moon rotates. When observing the Moon, many features are best observed when they are near the terminator, where shadows are long and plentiful. The shadows provide higher contrast between surface features.
The mountain range Montes Alpes is one of the prominent mountain ranges along the eastern border of Mare Imbrium. The range is named for the Alps on Earth, and the peak Mons Blanc is named for the tallest peak in the Alps of Earth—though Mons Blanc is actually the 3rd tallest peak of the Lunar Alpes. The range culminates to the south in the Promontorium Agassiz. To the north, the range terminates just shy of dark-floored crater Plato.
The Montes Apenninus, named for the Apennine Mountains in Italy, is a mountain range along the southeastern rim of the Mare Imbrium Impact basin (Sea of Showers). The Montes Apenninus contain some of the tallest mountains on the Near Side of the Moon.
This is the largest sinuous rille on the Moon. It is about 3 km wide at its western end, and widens up to 6 km toward the eastern end, where you will find the Cobra Head. The Cobra Head is a steep volcanic depression near the top of a mountaid at the end of the snake-like sinuous rille. Shcröter’s Valley may have been a major source of the lava that formed the Oceanus Procellarum.Schröter’s Valley is part of the Aristarchus Plateau, and is foundto the immediate northwest of the small, but very bright crater Aristarchus.
Vallis Alpes is a wide, 180 km long valley. It’s western end is in the Montes Alpes at the northeastern edge of the Mare Imbrium, and its western end terminates at the edge of the northern Mare Frigoris. This split in the lunar crust probably formed in response to the impact that created the Imbrium Basin. At the floor of the Alpine Valley is a long rille from which lava once erupted.
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Nightly Observing Program. Most of the above images were taken as
the Overnight Telescope Observing Program. For more information on this unique experience please visit Overnight Telescope Observing Program.
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