Celestron CGEM II 1100 EdgeHD Mode D'emploi page 2

light-gathering power for the dollar. Because the light path
is intercepted and reflected out to the side, you can have
focal lengths up to 1000 mm and still enjoy a telescope that
is relatively compact and portable. A Newtonian Reflector
telescope offers such impressive light-gathering characteristics
you can take a serious interest in deep space astronomy even
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The schmidt-Cassegrain optical system (Schmidt-Cass or
SCT for short) uses a combination of mirrors and lenses and
is referred to as a compound or catadioptric telescope. This
unique design offers large-diameter optics while maintaining
very short tube lengths, making them extremely portable. The
Schmidt-Cassegrain system consists of a zero power corrector
plate, a spherical primary mirror, and a secondary mirror. Once
light rays enter the optical system, they travel the length of the
optical tube three times.
Focal
Plane
Focuser
Secondary
Mirror
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on a modest budget. Newtonian Reflector telescopes do
require more care and maintenance because the primary mirror
is exposed to air and dust. However, this small drawback does
not hamper this type of telescope's popularity with those who
want an economical telescope that can still resolve faint,
distant objects.
Primary
Mirror
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ewtoniAn opticAl design
Inside the optical tube, a black tube extends out from the
center hole in the primary mirror. This is the primary baffle tube
and it prevents stray light from passing through to the eyepiece
or camera.
The Maksutov optical system is similar to the Schmidt-
Cassegrain but can have a secondary mirror or an aluminized
spot in place of the secondary mirror. There are many variations
of the Maksutov design.
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chmidt AssegRAin opticAl design
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