Step 10 General Cautions - Vixen GREAT POLARIS GP-DX Instruction Manual

Step 10 General Cautions
(T)Try never to view through glass windows when observing. Clear as window glass seems, compared to the fine optical glass of
your telescope, it produces very distorted images. If the observation is undertaken through an open window, air movement
through the window (owing to the temperature difference between the inside and outside air) may cause image instability,
resulting in distortion.
(2)Be sure the optical axis of the telescope is centered. If the optical axis of the telescope is out of center, the image of an object
is lengthened or is unnecessarily coloured.
3)Stars other than the Sun can not be observed in an enlarged image, because they are very far from the earth as compared with
the Sun or other planets. However, your telescope can show you millions of stars not visible to the naked eye.
(DTrain your eye for observation. The figure of a celestial object observed through a telescope looks different depending upon the
experience of the observer. With repeated observation experience, you will begin to see objects that you could not earlier observe.
Sometimes averted vision-glancing slightly away from an object will help you see more detail.
©Stars appear to move very fast. Because a telescope tracks an object at high magnification for observation, the apparent
movement of an object seems rapid. For instance, when observing Jupiter at a magnification of 100, the moving planet takes
only about one minute and thirty seconds from the time when it first appears in the eyepiece to the time when it disappears.
We call this apparent motion because most of the motion is really the earth rotating under us !
((Newtonian Reflector
Primary-Mirror Cell
| Secondary-Mirror Support Arm and Adjustment Screws
The secondary mirror is of critical importance to the
proper operation of your telescope. Never turn the
adjustment screws except when you correct the
optical axis.
There are three pairs of
screws on the back of
the primary-mirror cell.
Never turn these screws
except when you cor¬
rect the optical axis.
When observing an object soon after taking the
telescope outside, you can sometimes see the
object appear to fluctuate. This is because warm
air and cold air are mixing in the tube. If possible,
expose the telescope to the open air for 20 to 30
minutes before observing, so that tube tempera¬
ture stabilizes.
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