Celestron CGEM II 1100 EdgeHD Mode D'emploi

A telescope is an instrument that collects and focuses light.
The nature of the optical design determines how the light is
focused. Some telescopes (known as refractors) use lenses and
other telescopes, known as reflectors (Newtonians), use mirrors.
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Developed in the early 1600s, the refractor is the oldest
telescope design. It derives its name from the method it uses
to focus incoming light rays. The refractor uses a lens to bend
or refract incoming light rays, hence the name. Early designs
used single element lenses. However, the single lens acts like
a prism and breaks light down into the colors of the rainbow,
a phenomenon known as chromatic aberration. To get around
this problem, a two-element lens, known as an achromat, was
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A newtonian reflector uses a single concave mirror as its
primary mirror. Light enters the tube traveling to the mirror
at the back end. There light is bent forward in the tube to a
single point, its focal point. Since putting your head in front
of the telescope to look at the image with an eyepiece would
keep the reflector from working, a flat mirror called a diagonal
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elescope
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English
Then, the Schmidt-Cassegrain and Maksutov telescopes use
both mirrors and lenses. Each optical design is briefly
discussed below:
introduced. Each element has a different index of refraction
allowing two different wavelengths of light to be focused at the
same point. Most two-element lenses, usually made of crown
and flint glasses, are corrected for red and green light. Blue
light may still be focused at a slightly different point. Higher
priced units use ED (low dispersion) or apochromatic (APO)
optical designs to virtually eliminate chromatic aberration.
Objective
Lens
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intercepts the light and points it out the side of the tube at
right angles to the tube. The eyepiece is placed there for
easy viewing.
Newtonian Reflector telescopes replace heavy lenses with
mirrors to collect and focus the light, providing much more
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