RaySociety - Drake University
VOYAGES OF DISCOVERY: IN OUR SOLAR SYSTEM
http://edu-observatory.org/cfs/
by Sam Wormley
swormley1@mchsi.com
Thursdays 10:30 a.m. - Noon Medbury 221
April 5 -- May 3, 2007
Week 5 (May 3)
Moon
http://edu-observatory.org/eo/moon.html
http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?Earthrise
http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?Moon
http://www.lpod.org/
To The Moon 59 min
http://www.pbs.org/wgbh/nova/transcripts/2610tothemoon.html
Origins: Earth is Born (and Moon)
http://www.pbs.org/wgbh/nova/transcripts/3111_origins.html
"I think the biggest single surprise was that the materials
on the moon have exactly the same chemistry as the Earth and
different from any samples that we have anywhere else in the
solar system. So that pretty well forced the idea that the
moon has to have formed from the same basic material as the
Earth". -- William Hartmann (planetary astronomy)
The Clementine Mission - Ice on the Moon
http://www.cmf.nrl.navy.mil/clementine/
http://astrogeology.usgs.gov/Projects/Clementine/
http://www.spds.nasa.gov/planetary/clementine.html
Lunar Reconnaissance Orbiter
http://lro.larc.nasa.gov/
http://news.nationalgeographic.com/news/2006/04/0410_060410_moon.html
"The probe's impact is expected to create a plume of debris
that may vault 40 miles (65 kilometers) above the moon's
surface. The shepherding spacecraft will then fly through
that plume. Its instruments will analyze the cloud to look
for signs of water ice and other compounds".
Tides
http://www.learner.org/resources/series42.html
http://140.90.121.76/restles1.html
The Night Sky
The Earth rotates about its polar axis once a day and
produces an apparent motion on the night sky about the
celestial poles. In the Northern Hemisphere the north
celestial pole is elevated above the horizon. Facing away
from the elevated celestial pole, an observer sees the Sun,
Moon, planets, and stars rise in the east and set in the
west. They reach their highest altitude as they cross the
local meridian. When the observer turns to face the elevated
celestial pole, stars nearest the pole neither rise nor set.
They become circumpolar and cross the meridian each day once
above the pole at their highest altitude and once below the
pole at their lowest altitude. In the Northern Hemisphere,
circumpolar stars appear to rotate about the north celestial
pole counterclockwise. In the Southern Hemisphere the effect
is reversed and they appear to rotate clockwise.
Superimposed on the diurnal rotation is an annual rotation
caused by the Earth's orbiting the Sun. Since the stars are
seen by the naked eye after sunset, the constellations appear
to move from east to west, and to return to the same position
after a year. Relative to the Sun, the stars rise and set
roughly four minutes earlier each day. In the course of a
month, the night sky appears to move two hours in right
ascension to the west. Also because of this orbital motion of
the Earth, the circumpolar stars in the Northern Hemisphere
appear to rotate once a year in a counterclockwise direction
around the north celestial pole and in a clockwise direction
about the south celestial pole.
The Moon moves in an orbit inclined to the ecliptic by 5.1
degrees; the Moon makes one revolution about the sky from
west to east in about a month. During this period the phases
on the Moon complete a cycle from new to full and back to
new. The orbit of the Moon is moving around the ecliptic, so
that other aspects of the Moon's position in the sky, such as
its maximum and minimum declination, change from one month
the next. It is important to know when the planets are in the
most favorable position for observation. The outer planets,
for example, are best seen around opposition. They are in
their least favorable position around conjunction.
The inner planets are different--they are in their most
favorable position near greatest elongation, even though they
are not at full phase. At superior conjunction the phase is
around full, but the planets are difficult to see because
they are further from Earth and usually too close to the Sun.
At inferior conjunction the inner planets are nearest to the
Earth, but again they are difficult to see because their
phase is small, and they are too close to the Sun.
Often the times of phenomena need not have any great
precision; sometimes the nearest hour, day, or even the
nearest week are sufficient for observational purposes. The
dates and times, however, usually depend on the coordinate
system. For historical reasons the conjunctions and
oppositions of planets have always been calculated in
geocentric ecliptic coordinates. On the other hand, the
conjunctions of planets with other planets, bright stars, or
the Moon have always been calculated using equatorial
coordinates; the phenomena are then observed more easily with
an equatorially mounted telescope. In some cases the times of
phenomena have been defined as the maxima or minima of the
distances from the Sun or the Earth or the elongation from
another body. In such cases, the phenomena are independent of
the coordinate system.
From the Explanatory Supplement To The Astronomical Almanac (1992)
swormley1@mchsi.com