November 4, 2019 — Robert, NMM

Kitt Peak Nightly Observing Program

Splendors of the Universe on YOUR Night!

Many pictures are links to larger versions.
Click here for the “Best images of the OTOP” Gallery and more information.


Theophilus is a prominent impact crater that lies south of Mare Tranquilitatis, and northwest of Mare Nectaris. It partially overlaps its neighbor of similar size, Cyrillus. To the east is the smaller crater Mädler. Theophilus was named after the 4th-century Coptic Pope Theophilus of Alexandria. The rim of Theophilus has a wide, terraced inner surface. It is 4,200 meters deep. The crater formed sometime 3.2 to 1.1 billion years ago. It has a striking central mountain, 1,400 meters high, with four summits, surrounded by a mostly otherwise flat floor. The Apollo 16 mission collected several pieces of basalt that are believed to be ejecta from the formation of Theophilus.

Apollo 15

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.

Mare Imbrium

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.

Jupiter and the Galilean Moons

Jupiter is the largest and most massive planet in our Solar System. All of the other planets combined would not have as much mass as Jupiter. In even a small telescope, some of Jupiter’s stripes can be seen. Jupiter’s darker stripes are known as bands, and its lighter stripes are known as zones. Swirling storms appear as spots—sometimes visible through telescopes. Jupiter’s famous Great Red Spot is generally visible when its on the side of Jupiter facing toward Earth.

Jupiter’s four largest moons are known as the Galilean Moons, named for Galileo, who was the first astronomer to study them in depth and determine that they were orbiting Jupiter. Their individual names are Io, Europa, Ganymede, and Callisto—in orbital order from closest to Jupiter to furthest out. Ganymede is the largest of these four moons, and is the largest moon in our Solar System. Io, the closest of these four moons to Jupiter, is the most volcanic world in our Solar System. Io is home to hundreds of active volcanos. Its neighbor, and the next furthest from Jupiter of the four, Europa, is a dramatic contrast to Io with its icy surface. Europa is covered by water, which is frozen solid at the surface. The furthest our of the four, Callisto is a fascinating world in our Solar System because it is so utterly geologically dead. Without weather, moonquakes, volcanism, or any other surface-altering processes, Callisto’s surface is billions of years old—a kind of record of the history of the Solar System.


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.

Montes Apenninus

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.

Valles Alpes

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.

Your Telescope Operator and Guide. Thank you for joining me this evening! See you soon!!

The web page for the program in which you just participated is at
Nightly Observing Program. Most of the above images were taken as
part of
the Overnight Telescope Observing Program. For more information on this unique experience please visit Overnight Telescope Observing Program.
Copyright © 2019 Kitt Peak Visitor Center

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