Orion AstroView 9005 - Manual (Page 11)

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c. d.
Figure 9. This illustration shows the telescope pointed in the four cardinal directions: (a) north, (b) south, (c) east, (d) west. Note that the
tripod and mount have not been moved; only the telescope tube has been moved on the R.A. and Dec. axes.
a. b.
weight shaft is horizontal (parallel to the ground). Then loosen
the Dec. lock lever and rotate the telescope until it is pointing
straight overhead. The counterweight shaft is still horizontal.
Then retighten both lock levers.
What if you need to aim the telescope directly north, but at an
object that is nearer to the horizon than Polaris? You can’t do
it with the counterweight down as pictured in Figure 1. Again,
you have to rotate the scope in R.A. so that the counterweight
shaft is positioned horizontally. Then rotate the scope in Dec.
so it points to where you want it near the horizon.
To point the telescope directly south, the counterweight shaft
should again be horizontal. Then you simply rotate the scope
on the Dec. axis until it points in the south direction.
To point the telescope to the east or west, or in other directions,
you rotate the telescope on its R.A. and Dec. axes. Depending on
the altitude of the object you want to observe, the counterweight
shaft will be oriented somewhere between vertical and horizon-
tal.
Figure 9 illustrates how the telescope will look when pointed
at the four cardinal directions—north, south, east and west.
The key things to remember when pointing the telescope are
that a) you only move it in R.A. and Dec., not in azimuth or
latitude (altitude), and b) the counterweight and shaft will not always appear as it does in Figure 1. In fact it almost never
will!
6. using Your telescope—
Astronomical Observing
Choosing an Observing Site
When selecting a location for observing, get as far away as
possible from direct artificial light such as streetlights, 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) window, because the tempera-
ture difference between the indoor and outdoor air will cause
image blurring and distortion.
If at all possible, escape the light-polluted city sky and head
for darker country skies. You’ll be amazed at how many more
stars and deep-sky objects are visible in a dark sky!