Operation Manual

Looking at or near the Sun will cause instant and irreversible damage to your eye!
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ap p e n d I x d: ba s I c a s t r o n o m y
Appendix D: Basic astronomy
In the early 17th century Italian Scientist Galileo, using a telescope smaller
than your Messier, turned it skyward instead of looking at the distant trees
and mountains. What 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 phases of Venus! Because
of his observations, Galileo correctly realized Earth‘s movement and posi-
tion 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 determined 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
understood. 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 variable stars, the Moon, and our solar system comes from observations
made by amateur astronomers. So as you look through your Bresser
Messier-Series telescope, keep in mind Galileo. To him, a telescope was not
merely a machine made of glass and metal, but something far more—a win-
dow of incredible discovery. Each glimpse offers a potential secret waiting to
be revealed.
Objects in Space
Listed below are some of the many astronomical objects that can be seen
with your Messer 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 surface at an angle. It casts shadows and adds a sense
of depth to the view (Fig. 50).
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 filter 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 Messier-Series telescope, brilliant detail can be observed on the
Moon, including 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.
Fig. 42: The moon. Note the deep
shadows in the craters.
Fig. 43: The giant planet, Jupiter.
The four largest moons can be
observed in a different position
every night.
Fig. 43a: Jupiter, here in a higher
magnification. Note the detailed
cloud structures.