ASTR 130, O'CONNELL. LUNAR TOPOGRAPHY
LUNAR TOPOGRAPHY
This is a composite image of the near side of the Moon taken from an
Earth-based telescope. It is constructed from two images taken at
first and last quarter so that it shows maximum detail in the center
of the Moon's face. The distinction between smooth maria and rough
highland regions is emphasized in the image, as are the circular
outlines of the maria. Click on the image for a larger version.
EARTH-BASED PHOTOGRAPHS
Mosaic image of the Appenine-Caucasus Mountains, adjacent to Mare
Senenitatis, made with a CCD camera by amateur astronomer Alessandro
Bares.
Image showing shadows cast by peaks near the "terminator" (twilight line on
the Moon's surface). The shadows allow the height and the shape of lunar
mountains to be determined.
The "Straight Wall" in Mare Nubium, a fault line extending 120 km. Image
by T. Legault.
Hadley Rille, the best example of a "sinuous rille," or valley, caused by lava
flows. See the spacecraft image of the rille below.
SPACECRAFT PHOTOGRAPHS
Moon's surface as imagined by famous space artist Chesley Bonestell, early 1950's.
Same spaceship design was used in movie "Destination Moon," for which
Bonestell was a technical advisor. A "half Earth" hovers over the mountains.
Topographic map in false color of the altitude of the Moon's surface
obtained by the Clementine orbiter mission (1994). Measurements made
with a laser altimiter. Redder areas are higher, blue/purple areas
lower. The altitude difference between the maria and the highlights
is obvious here. There is a strong asymmetry between the near and far
sides. Also note the large Aitken impact basin near the lunar South
Pole, seen on the far side. This is 2500 km in diameter and 13 km
deep, making it the largest impact basin in the solar system. Much of
it is in perpetual shadow, at temperatures of less than 50 K.
Click on the image for a larger
version.
Lunar terrain types in false color, highlighting differences in
surface minerals. This mosaic was constructed from a
series of 53 images taken through three spectral filters by Galileo's
imaging system as the spacecraft flew over the northern regions of the
Moon on December 7, 1992. The part of the Moon visible from Earth is
on the left side in this view. The color mosaic shows compositional
variations in parts of the Moon's northern hemisphere. Bright pinkish
areas are highlands materials, such as those surrounding the oval
lava-filled Crisium impact basin toward the bottom of the picture.
Blue to orange shades indicate volcanic lava flows. To the left of
Crisium, the dark blue Mare Tranquillitatis is richer in titanium than
the green and orange maria above it. Thin mineral-rich soils
associated with relatively recent impacts are represented by light
blue colors; the youngest craters have prominent blue rays extending
from them. [Source: Galileo Project, Jet Propulsion Laboratory]
This is an image taken by Apollo 17 (December 1972). The view is
looking south from orbit over the southern edge of Mare Imbrium. The
large crater at left center is Erathosthenes. Terrain around the
crater is older and more rugged than the mare plains at the bottom of
the picture. Note the mountain-like formations in the center of the
crater, produced by impact "bounceback." The crater just visible
edge-on on the lunar horizon at the lower right is Copernicus.
The hills at the left of Eratosthenes are the eastern end of the Apennine
Mountain range, which line the southeastern quadrant of Mare Imbrium. Lunar
mountains are produced by impact events, not by plate tectonics. Note the
steep rise of the hills out of the mare plain.
A small rille, or canyon, caused presumably by lava flow, is
visible extending toward the camera from the slopes of Eratosthenes.
A crater in the rugged highlands region on the Moon's far side. Also contains
"bounceback" hills in its center.
A view looking down on the landing site of Apollo 15 near the
mile-wide Hadley Rille. This is one of the largest rilles on the
Moon, lying at the southeast edge of Mare Imbrium. Hadley Rille is 75
miles long and up to 950 feet deep. It was produced by a lava flow
about 3.3 billion years ago. Note the flat mare terrain, apart from
the Rille itself. Click here for a
wide angle view of the Rille.
Southward looking oblique view of Mare Imbrium and Copernicus crater.
Copernicus is seen almost edge-on near the horizon at the center. The
crater is 107 km in diameter and is centered at 9.7 N, 20.1 W. In the
foreground is Mare Imbrium, peppered with secondary crater chains and
elongated craters due to the Copernicus impact. The smoother mare
surface is in contrast to the rough highland area at the top of the
frame. The large crater near the center of the image is the 20 km
diameter Pytheas, at 20.5 N, 20.6 W. At the upper edge of Mare
Imbrium are mountains (Montes Carpatus) produced by the Imbrium
impact. The distance from the lower edge of the frame to the center
of Copernicus is about 400 km. This picture was taken by the metric
camera on Apollo 17. Click on the image for a larger version.
[Source: NASA NSSDC]
Apollo 15 metric camera image of Southeastern Mare Imbrium. The 33 km
diameter Timocharis crater, centered at 26.7 N, 13.1 W, is partly
visible at upper left. Note the old fractured terrain at the right
and smoother textured and ridged mare terrain at center. The craters
Feuillee and Beer(!) are at the top of the image, and just below at
right of Beer a small crater chain can be seen. A sinuous rille is
also visible at bottom center of the image, running up to middle of
the frame. The image is about 115 km across and north is up. Note
the strong shadows cast by the low sun angle. Altitudes of peaks like
those seen to the right in the image can be determined by measuring
these shadows from Earth-based telescopes and applying simple
trigonometry. Click on the image for a larger version. [Source:
NASA NSSDC]
Oblique view of the highland area surrounding the ancient 138 km
diameter crater Hipparchus. The crater is centered near the middle of
the image and stretches over half the width of the frame but is barely
visible due to more recent impact activity since it was formed. It
has been partially filled in by impact debris. The radial grooves and
ridges are related to the Imbrium impact and are known as "Imbrium
sculpture." Near the horizon at left is Sinus Medii. The crater
within Hipparchus above and right of center is Horrocks, 30 km in
diameter. North is up. Click on the image for a larger
version.[Source: NASA NSSDC]
Full moon rises over Earth limb. Photo taken from orbit at 190 miles
altitude by Space Shuttle Columbia during Astro-1 Spacelab mission. Click for
full version.
Last modified
Octboer 2004 by rwo
Non-public text copyright © 1998-2004 Robert W.
O'Connell. All rights reserved. These notes are intended for the
private, noncommercial use of students enrolled in Astronomy 130 at the
University of Virginia.
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