ORION TELESCOPES & BINOCULARS Observer II User Manual

6
change, the more time is needed. Allow at least 30 minutes
for your telescope to acclimate to the temperature outdoors
before you start observing with it.
Let Your Eyes Dark-Adapt
Don’t expect to go from a lighted house into the darkness of
the outdoors at night and immediately see faint nebulas, gal-
axies, and star clusters—or even very many stars, for that mat-
ter. Your eyes take about 30 minutes to reach perhaps 80% of
their full dark-adapted sensitivity. As your eyes become dark-
adapted, more stars will glimmer into view and you’ll be able
to see fainter details in objects you view in your telescope.
To see what you’re doing in the darkness, use a red-ltered
ashlight rather than a white light. Red light does not spoil
your eyes’ dark adaptation like white light does. A ashlight
with a red LED light is ideal. Beware, too, that nearby porch,
streetlights, and car headlights will ruin your night vision.
Eyepiece Selection
Magnication, 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 magnication can be varied. It is quite common for
an observer to own ve or more eyepieces to access a wide
range of magnications. This allows the observer to choose
the best eyepiece to use depending on the object being
viewed and viewing conditions. Your Observer II 60mm refrac-
tor comes with 25mm (N) and 10mm (O) Kellner eyepieces,
which will suffice nicely to begin with. You can purchase addi-
tional eyepieces later if you wish to have more magnication
options.
Magnication is calculated as follows:
Telescope Focal Length (mm) / Eyepiece
Focal Length (mm) = Magnication
For example, the Observer II 60mm refractor has a focal
length of 700mm, which when used with the supplied 25mm
eyepiece yields:
700mm / 25mm = 28x
The magnication provided by the 10mm eyepiece is:
700mm / 10mm = 70x
The maximum attainable magnification for a telescope is
directly related to how much light it can gather. The larger the
aperture, the more magnication is possible. In general, a g-
ure of 50x per inch of aperture is the maximum attainable for
most telescopes. Going beyond that will yield simply blurry,
unsatisfactory views. Your Observer II 60mm refractor has an
aperture (primary mirror diameter) of 60mm, or 2.4 inches,
so the maximum magnication would be about 118x (2.4 x
50). This level of magnication assumes you have ideal atmo-
spheric conditions for observing (which is seldom the case).
Figure 6. Thread the accessory tray onto the tripod leg brace;
the screw on the underside of the tray threads into the socket in
the center of the brace.
Turn to tighten
Figure 7.
The assembled
altazimuth mount
and tripod.
Figure 8. a) Place the optical tube in the yoke mount, lining up
the holes in the tube’s attachment plates with those in the yoke
mount. b) Thread the yoke knob into the threaded hole in the
attachment plates.
Attachment plate
a
b

ORION TELESCOPES & BINOCULARS Observer II Specifications

General

Brand	ORION TELESCOPES & BINOCULARS
Model	Observer II
Category	Telescope
Language	English