Meade Instruments LX80 - Manual (Page 21)

at least 200 yards away. If the distant object is not
in focus, turn the focus lock ring counterclockwise
to loosen the viewfi nder front cell (Page 8, Fig 1,
3). Twist the front cell until focus is achieved and
retighten the focus lock ring.
4. Unlock the RA lock (Page 8, Fig 1, 29) and the
DEC lock (Page 8, Fig 1, 30) so that the telescope
turns freely on both axes. Then point the main
telescope at a tall, well-defi ned and stationary
land object (e.g., the top of a telephone pole) at
least 200 yards distant and center the object in the
telescope’s eyepiece. Focus the image by turning
the optical tube focus knobs (Page 8, Fig 1, 11).
Retighten the RA and DEC locks and verify the
object is still centered in the eyepiece.
5. Look through the viewfi nder and loosen or tighten,
as appropriate, one or more of the viewfi nder
collimation thumbscrews (Page 8, Fig 1, 2) until
the viewfi nder’s crosshairs are precisely centered
on the object you previously centered in the main
telescope’s eyepiece.
NEVER point the telescope or viewfi nder directly
at or near the Sun at any time! Observing the Sun,
even for the smallest fraction of a second, will
result in instant and irreversible eye damage, as
well as physical damage to the telescope itself.
Check this alignment on a celestial object, such as
a bright star or the Moon, and make any necessary
refi nements, using the method outlined above in steps
4 & 5.
With this alignment performed, objects fi rst located
in the wide-fi eld viewfi nder will also appear in the
telescope’s eyepiece.
Choosing an Eyepiece
A telescope’s eyepiece magnifi es the image formed by
the telescope’s main optics. Each eyepiece has a focal
length, expressed in millimeters, or “mm.” The smaller
the focal length, the higher the magnifi cation. For
example, an eyepiece with a focal length of 9mm has
a higher magnifi cation than an eyepiece with a focal
length of 26mm when used with the same OTA.
Your telescope comes supplied with an eyepiece which
gives a wide, comfortable fi eld of view with high image
resolution.
Low-power eyepieces offer a wide fi eld of view,
bright, high-contrast images, and eye relief during
long observing sessions. To fi nd an object with a
telescope, always start with a lower power eyepiece
such as the 26mm. When the object is located and
centered in the eyepiece, you may wish to switch
to a higher power eyepiece to enlarge the image as
much as practical for prevailing seeing conditions.
For information about optional eyepieces for the LX80
Series models, see OPTIONAL ACCESSORIES,
Page 52.
The power, or magnifi cation of a telescope is
determined by the focal length of the telescope and the
focal length of the eyepiece being used. To calculate
eyepiece power, divide the telescope’s focal length
by the eyepiece’s focal length. For example, a 26mm
eyepiece is supplied with the LX80 Series. The focal
length of the 8” LX80 Series SC model is 2034mm (see
Specifi cations, Page 60).
Telescope Focal Length ÷ Eyepiece Focal Length
= Magnifi cation (Power)
Telescope Focal Length = 2034mm
Eyepiece Focal Length = 26mm
2034 ÷ 26 = 78
The eyepiece power, or magnifi cation is therefore 78X
(approximately).
Observing by Moving the Telescope
Manually
After the telescope is assembled and balanced as
described previously, you are ready to begin manual
observations. View easy-to-fi nd terrestrial objects such
as street signs or traffi c lights to become accustomed
to the functions and operations of the telescope.
For the best results during observations, follow the
suggestions below:
• When you wish to locate an object to observe, fi rst
loosen the telescope’s RA lock (Page 8, Fig 1, 29)
and DEC lock (Page 8, Fig 1, 30). The telescope
can now turn freely on its axes. Unlock each axis
separately and practice moving your telescope.
Then practice with two unlocked axes at the same
time. It is especially important to practice this
step to understand how your telescope moves in
equatorial confi guration, as the movement of an
equatorial mount are not intuitive.
• Use the aligned viewfi nder to sight-in on the object
you wish to observe. When the object is centered
in the viewfi nder’s crosshairs, re-tighten the RA
21
Getting Started