Telescope Types And Optical Systems - Globaltronics GT-Tel-02 REFRACTOR Gebrauchsanleitung

TELESCOPE TYPES AND OPTICAL SYSTEMS

More than 3 centuries ago, Galileo Galilei directed a small telescope toward the stars, and the
modern age of the science began. There are two main groups of telescopes: terrestrial tele-
scopes and astronomical telescopes. The main difference is that the terrestrial telescope, which
is intended for seeing objects on the Earth, provides an upright or normal image, while the
astronomical telescope provides a rotated image that stands on its head. While it is important
for Earth-bound objects, to see them in their normal position, for astronomical observations, this
is not important.
Objective lens
Galileo telescope system
The reason that astronomical telescopes generally show a reversed image is that, in contrast to
terrestrial telescope, they posses no specialised erecting lens system. Although the additional lens
system provides an upright image, it causes a slight loss of light. In an astronomical that is used for
extremely weak object, it is important to reduce the loss of light to a minimum. This does not mean
that the terrestrial telescopes cannot be used for astronomical observations. They are only not able
to show a weak object as well as an astronomical telescope.
Objective lens
Telescope
Objective lens
Astronomical telescopes are furthermore split into two categories, which depend on the optical
system used. The refractor only uses lenses for magnification, while the reflector uses two mir-
rors, in place of the lenses.
Eye
Telescope
Eyepiece
De ection mirror
Newton mirror telescope system
Astronomical telescope system
Telescope system for Earth observation
Eyepiece
Eyepiece
Eye
Eyepieces
Objective mirror
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Eye