5
2. Point the main telescope at a discrete object such as the
top of a telephone pole or street sign that is at least 200
yards away. Move the telescope so the target object
appears in the very center of the field of view, when you
look into the eyepiece. Now tighten the altitude lock knob
(remember, just “finger tight” so you don’t strip the
threads), and slightly tighten the azimuth and yoke knobs
(so that slight movement is still possible with light pressure
on the telescope tube). Use the altitude micro-motion con-
trol knob and slight sideways pressure on the main
telescope tube to re-center the object in the field of view,
if it moved off center when you tightened the lock knobs.
3. Now look through the finder scope. Is the object centered in
the finder scope’s field of view, i.e., on the crosshairs? If not,
hopefully it will be visible somewhere in the field of view, so
that only fine adjustment of the alignment screws will be
needed to center it on the crosshairs. If the object isn’t in the
field of view at all, you’ll have to make coarser adjustments to
the alignment screws to redirect the aim of the finder scope.
4. The two spring-tensioned alignment screws on the finder
scope bracket make alignment of the finder scope very easy.
You don’t need to adjust them, only the other four alignment
screws. By loosening one alignment screw and tightening
another, you change the line of sight of the finder scope.
5. Once the target object is centered on the crosshairs of the
finder scope, look again in the main telescope’s eyepiece
and see if it is still centered there as well. If it isn’t, repeat
the entire process, making sure not to move the main
telescope while adjusting the alignment of the finder
scope.
6. Check the alignment by pointing the main telescope at
another object and centering it in the finder scope. Then
look through the main telescope eyepiece and see if the
object is centered. If it is, your job is done. If it isn’t, make
the necessary adjustments to the finder scope’s alignment
screws until the object is centered in both instruments.
7. Finder scopes often come out of alignment during transport
of the telescope, so check it before each observing session.
One way to minimize any misalignment is to keep the finder
scope bracket tightly fastened to the main telescope.
8. Note that the image seen through the finder scope appears
upside-down. This is normal for astronomical finder scopes.
5. using Your telescope
choosing an observing site
When selecting a location for observing, get as far away as pos-
sible from direct artificial light such as street lights, porch lights,
and automobile headlights. The glare from these lights will
greatly impair your dark-adapted night vision. Set up on a grass
or dirt surface, not asphalt, because asphalt radiates more heat.
Heat disturbs the surrounding air and degrades the images seen
through the telescope. Avoid viewing over rooftops and chimneys,
as they often have warm air currents rising from them. Similarly,
avoid observing from indoors through an open (or closed) win-
dow, because the temperature difference between the indoor and
outdoor air will cause image blurring and distortion.
It’s best, although perhaps less convenient, to escape the light-
polluted city sky in favor of darker country skies. You’ll be amazed at
how many more stars and deep-sky objects are visible in a dark
sky!
cooling the telescope
All optical instruments need time to reach “thermal equilibrium.”
The bigger the instrument and the larger the temperature
change, the more time is needed. Allow at least a half-hour for
your telescope to cool to the temperature outdoors. In very cold
climates (below freezing), it is essential to store the telescope as
cold as possible. If it has to adjust to more than a 40° tempera-
ture change, allow at least one hour. Make sure you are not
looking over buildings, pavement, or any other source of heat,
which will radiate away at night, causing “heat wave” distur-
bances that will distort the image you see through the telescope.
aiming the telescope
To aim the telescope, first loosen both the azimuth and altitude lock
knobs, and slightly loosen one of the yoke knobs. Aim the telescope
at the object you wish to observe by first “eyeballing” along the length
of the telescope tube. Then look through the (aligned) finder scope and
move the telescope tube until the object is visible in the finder scope.
Center it on the finder’s crosshairs. Then tighten the lock knobs. You
should now be able to see the object in the main telescope using a
low-power eyepiece. (Always use the lowest-power eyepiece available
for locating an object, then you can switch up to higher powers if
desired.)
Fine adjustments in the telescope’s vertical position can be
made by rotating the altitude micro-motion knob (make sure
the altitude lock knob is tightened first). Fine adjustments in
the azimuth position can be made by applying slight sideways
pressure to the back end of the telescope (make sure the
azimuth lock knob is slightly loosened).
Note: The altitude micro-motion knob has a limited range
of movement. If you reach the end of the travel range,
loosen the altitude lock bolt and rotate the micro-motion
knob back a few turns, then tighten the lock bolt again.
Focusing the telescope
Practice focusing the telescope in the daytime before using it
for the first time at night. Start by positioning the focuser draw-
tube near the center of its adjustment range. Insert an
eyepiece into the star diagonal and secure with the thumb-
screw. Point the telescope at a distant subject and get it in the
field of view. Now, slowly rotate one of the focusing knobs until
the object comes into sharp focus. Go a little bit beyond sharp
focus until the image just starts to blur again, then reverse the
rotation of the knob, just to make sure you hit the exact focus
point. The telescope can only focus on objects at least 50 to
100 feet away. It will not focus without the star diagonal in
place.
As with all refractor telescopes used with a standard 90° star
diagonal, the image you see will be right-side up, but reversed left-