Appendix F: Basic Astronomy - Meade LXD 75 Instruction Manual

Fig. 56 The Moon. Note
the deep shadows in the
craters.
APPENDIX F:
BASIC ASTRONOMY
In the early 17th century Italian Scientist Galileo, using a telescope smaller than your
, turned it skyward instead of looking at the distant trees and mountains. What
LXD75
he saw, and what he realized about what he saw, has forever changed the way
mankind thinks about the universe. Imagine what it must have been like being the first
human to see moons revolve around the planet Jupiter or to see the changing phas-
es of Venus! Because of his observations, Galileo correctly realized Earth's movement
and position around the Sun, and in doing so, gave birth to modern astronomy. Yet
Galileo's telescope was so crude, he could not clearly make out the rings of Saturn.
Galileo's discoveries laid the foundation for understanding the motion and nature of
the planets, stars, and galaxies. Building on his foundation, Henrietta Leavitt deter-
mined how to measure the distance to stars, Edwin Hubble gave us a glimpse into the
possible origin of the universe, Albert Einstein unraveled the crucial relationship of
time and light, and 21st-century astronomers are currently discovering planets around
stars outside our solar system. Almost daily, using sophisticated successors to
Galileo's telescope, such as the Hubble Space Telescope and the Chandra X-Ray
Telescope, more and more mysteries of the universe are being probed and under-
stood. We are living in the golden age of astronomy.
Unlike other sciences, astronomy welcomes contributions from amateurs. Much of the
knowledge we have on subjects such as comets, meteor showers, double and vari-
able stars, the Moon, and our solar system comes from observations made by ama-
teur astronomers. So as you look through your Meade
in mind Galileo. To him, a telescope was not merely a machine made of glass and
metal, but something far more—a window of incredible discovery. Each glimpse offers
a potential secret waiting to be revealed.
Autostar Glossary
Be sure to make use of Autostar's Glossary feature. The Glossary menu provides an
alphabetical listing of definitions and descriptions of common astronomical terms.
Access directly through the Glossary menu or through hypertext words embedded in
Autostar. See
GLOSSARY MENU
Objects in Space
Listed below are some of the many astronomical objects that can be seen with your
:
LXD75-Series telescope
The Moon
The Moon is, on average, a distance of 239,000 miles (380,000km) from Earth and is
best observed during its crescent or half phase when Sunlight strikes the Moon's sur-
face at an angle. It casts shadows and adds a sense of depth to the view (Fig. 56).
No shadows are seen during a full Moon, causing the overly bright Moon to appear
flat and rather uninteresting through the telescope. Be sure to use a neutral Moon fil-
ter when observing the Moon. Not only does it protect your eyes from the bright glare
of the Moon, but it also helps enhance contrast, providing a more dramatic image.
Using your
LXD75-Series telescope
ing hundreds of lunar craters and maria, described below.
Craters are round meteor impact sites covering most of the Moon's surface. With no
atmosphere on the Moon, no weather conditions exist, so the only erosive force is
meteor strikes. Under these conditions, lunar craters can last for millions of years.
Maria (plural for mare) are smooth, dark areas scattered across the lunar surface.
These dark areas are large ancient impact basins that were filled with lava from the
interior of the Moon by the depth and force of a meteor or comet impact.
Twelve Apollo astronauts left their bootprints on the Moon in the late 1960's and early
1970's. However, no telescope on Earth is able to see these footprints or any other
artifacts. In fact, the smallest lunar features that may be seen with the largest tele-
scope on Earth are about one-half mile across.
LXD75-Series
, page 27, for more information.
, brilliant detail can be observed on the Moon, includ-
telescope, keep
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