Photo of the Week
Photographs of Full Moon
On October 5, 2006
(about 2 weeks ago) the astronomy students at Warren Wilson College
photographed the nearly full Moon through a telescope. The actual
full Moon occured at about 11:00 PM on Oct. 6, 2006, a little over one
day after these photos were taken.
techniques for photographing the full Moon involves a special eyepiece
fitted to an 8-inch telescope to which a digital camera is
attached. The special eyepiece is a tremendous help because it
holds the camera firmly in position. We used to do these photos
merely by handholding the digital camera close to the eyepiece.
Another important technique is to use a time-delay shutter
release. The time-delay allows the vibrations of the telescope
caused by pressing the shutter release to die-out. This allows an
Photographs of the full Moon show the darker areas - called maria - in
contrast to the lighter areas - called highlands. The dark maria
(Latin for "seas") were caused by catastrophic events early in the
Moon's history. It is believed that these catastrophic events
were collisions of the Moon with minor planets or large
asteroids. The giant craters ruptured the outer crust of the Moon
allowing the denser material from inside the primordial Moon to rise to
the surface. This darker material then solidified into the
relatively flat areas called the maria. Because the maria
material is more dense than the rest of the lunar surface, and because
the maria are predominantly on one side of the Moon, the side of the
Moon with the maria is "tidally locked" in the orbit around the
Earth. This is the main reason that the same side of the Moon
faces the Earth at all times.
There are a few relatively "recent" impacts on the Moon. These
are seen as craters with the rays of lighter material readiating out
from them. The most obvious is Tycho in the lower left with the
extensive ray system. Copernicus and Kepler are also prominent
"recent" impact craters in maria in the mid-upper-left parts of the
Further study of this image, and a closeup image shown at right,
reveals that the Moon was not quite full on Oct. 5. Dan Callaghan chose to zoom in on the upper left part
of the Moon. Notice that the topographic features of the craters
are visible in Dan's photo near the edge of the Moon. These
features are visible because the Moon was not quite full. These
craters lie at the "terminator" - the boundary between the sunlit part
of the Moon and the dark part of the Moon. At the terminator, the
sun is low to the lunar horizon and shadows are long and
enhanced. A partial phase Moon shows the topographical features
much more prominently. This occurs when the terminator falls on
the middle part of the Moon that faces Earth as in the PPOW for September
The full Moon for these photographs occured about two weeks ago.
If you look for the Moon tonight (October 20, 2006) you will not find
it because the Moon is "new" - between the Sun and the Earth. In
two weeks (November 3, 2006), when the next Physics Photo of the Week
will be published, the Moon will again be full. Due to fall
break, there will be no Physics Photo of the Week next week.
Photo of the
published weekly during the academic year on Fridays by the Warren
Wilson College Physics
Department. These photos feature an interesting phenomena in
the world around us. Students, faculty, and others are invited to
submit digital (or film) photographs for publication and
explanation. Atmospheric phenomena are especially welcome.
Please send any photos to firstname.lastname@example.org.
here to see the Physics Photo
the Week Archive.
are invited to submit
digital photos to: