Orion GOSCOPE 70 - Manual (Page 4)

4
Focusing the telescope
With the 20mm eyepiece inserted into the diagonal, move the
telescope so the front end is pointing in the general direc-
tion of an object at least 1/4-mile away. Now with your fingers,
slowly rotate the focus knob until the object comes into sharp
focus. Go a little bit beyond sharp focus until the image starts
to blur again, then reverse the rotation of the knob, just to
make sure you’ve hit the exact focus point.
Do You Wear Eyeglasses?
If you wear eyeglasses, you may be able to keep them on
while you observe. In order to do this, the eyepiece must have
enough “eye relief” to allow you to see the entire field of view
with glasses on. You can try this by looking through the eye-
piece first with your glasses on and then with them off, and
see if the glasses restrict the view to only a portion of the full
field. Fold down the rubber eyeguard on the eyepiece in order
to get your glasses (and eye) as close to the eyepiece lens as
possible. If the glasses do restrict the field of view, you may
be able to observe with your glasses off by just refocusing the
telescope by the needed amount.
If your eyes are astigmatic, images will probably appear the
best with glasses on. This is because a telescope’s focuser
can accommodate for nearsightedness or farsightedness,
but not astigmatism. If you have to wear your glasses while
observing and cannot see the entire field of view, you may
want to consider purchasing additional eyepieces that have
longer eye relief.
operating the EZ Finder ii
reflex sight
The EZ Finder II reflex sight (Figure 4) makes pointing your
telescope almost as easy as pointing your finger! It’s a non-
magnifying aiming device that superimposes a tiny red dot on
the sky, showing exactly where the telescope is pointed.
The EZ Finder II works by projecting a tiny red dot (it’s not
a laser beam) onto a lens mounted in the front of the unit.
When you look through the reflex sight, the red dot will appear
to float in space. The red dot is produced by a light-emitting
diode (LED) near the rear of the sight. A 3-volt lithium battery
provides the power for the diode.
Remove the clear plastic tab near the battery cover; this tab
prevents the batteries from accidentally being drained during
shipment. Turn the power knob clockwise until you hear the
“click” indicating that power has been turned on. Look through
the back of the reflex sight with both eyes open to see the red
dot. Position your eye at a comfortable distance from the back
of the sight. The intensity of the dot is adjusted by turning the
power knob. For best results when stargazing, use the dim-
mest possible setting that allows you to see the dot without dif-
ficulty. Typically a dimmer setting is used under dark skies and
a bright setting is used under light-polluted skies or daylight.
At the end of your observing session, be sure to turn the
power knob counterclockwise until it clicks off. When the two
white dots on the EZ Finder II’s body and power knob are
lined up, the EZ Finder II is turned off.
aligning the EZ Finder ii reflex sight
When the EZ Finder II is properly aligned with the telescope,
an object that is centered on reflex sight’s red dot should also
appear in the center of the field of view of the telescope’s eye-
piece. Alignment of the sight is easiest during daylight, before
observing at night.
1. Aim the telescope at a distant object such as a telephone
pole or roof chimney and center it in the telescope’s eye-
piece. The object should be at least 1/4 mile away. Now,
with the EZ Finder II turned on, look though it. The object
will appear in the field of view near the red dot.
2. Without moving the main telescope, use the EZ Finder
II’s azimuth (left/right) and altitude (up/down) adjustment
knobs (Figure 4) to center the red dot on the object in the
eyepiece.
3. When the red dot is centered on the distant object, check
to make sure that the object is still centered in the tele-
scope’s field of view. If not, re-center it and adjust the EZ
Finder II’s alignment again. When the object is centered
in the eyepiece and on the reflex sight’s red dot, the EZ
Finder II is properly aligned with the telescope and is
ready to be used.
The EZ Finder II alignment should be checked before every
observing session. Choose any distant target (during the day)
or bright star (at night), center the object in the telescope’s
eyepiece, then adjust the knobs until the object is centered on
the red dot of the reflex sight.
replacing the Battery
Should the battery ever die, replacement 3-volt lithium batter-
ies are available from many retail outlets. Remove the old bat-
tery by inserting a small flat-head screwdriver into the slot on
the battery cover (Figure 4) and gently prying open the cover.
Then carefully pull back on the retaining clip and remove the
old battery. Do not over bend the retaining clip. Then slide the
new battery under the battery lead with the positive (+) side
facing down and replace the battery cover.
Magnification & Eyepieces
Magnification, or power, is determined by the focal length of
the telescope and the focal length of the eyepiece being used.
Therefore, by using eyepieces of different focal lengths, the
resultant magnification can be varied. It is quite common for
an observer to own five or more eyepieces to access a wide
range of magnifications. This allows the observer to choose
the best eyepiece to use depending on the object being
viewed. The GoScope comes with two eyepieces, which will
suffice nicely to get started.
Magnification is calculated as follows:
Telescope Focal Length
= Magnification
Eyepiece Focal Length