Celestron C4.5 - The Newtonian Optical System Oi Ale E E Ee RI

The Newtonian Optical
System
NEVER USE AN EYEPIECE SOLAR FILTER OR A HERSCHEL WEDGE
SOLAR FILTER. INTERNAL HEAT BUILD-UP INSIDE THE TELE-
SCOPE CAN CAUSE THESE DEVICES TO CRACK OR BREAK ALLOW-
ING UNFILTERED SUNLIGHT TO PASS THROUGH TO THE EYE.
NEVER POINT YOUR TELESCOPE AT THE SUN UNLESS YOU HAVE
THE PROPER SOLAR FILTER. WHEN USING YOUR TELESCOPE
WITH THE CORRECT SOLAR FILTER, ALWAYS COVER THE FINDER.
ALTHOUGH SMALL IN APERTURE, THIS INSTRUMENT HAS
ENOUGH LIGHT GATHERING POWER TO CAUSE PERMANENT AND
IRREVERSIBLE EYE DAMAGE. FURTHERMORE, THE IMAGE PRO-
JECTED BY THE FINDER IS HOT ENOUGH TO BURN SKIN OR
CLOTHING.
The Newtonian reflector was developed by Isaac Newton in the early 1700's
and therefore carries his name. This type of telescope uses a parabolic
primary mirror to focus the light rays it collects. In addition to focusing the
light, the mirror also redirects it toward the front of the telescope tube where
the light entered. Near the front of the tube, the light rays are intercepted by
a small flat mirror (called an elliptical flat) and directed out of the telescope
tube at a 90° angle to the incoming light rays (see figure 1-1). It is here that
the eyepiece is placed to view the image formed by the telescope.
Figure 1-1
This cross sectional diagram shows the light path of the Newtonian
optical system.
Introduction * 3