SKY-WATCHER S11670 User Manual page 20

Telescopes with long focal lengths often
have a "blind spot" when pointing near the
1.
2.
zenith, because the eyepiece-end of the
optical tube bumps into the mount's legs
(Fig.r1). To adapt for this, the optical tube
can be very carefully slipped up inside the
tube rings (Fig.r2). This can be done safely
because the tube is pointing almost
vertically, and therefore moving it does not
cause a Dec-balance problem. It is very
important to move the tube back to the
Dec-balanced position before observing
other sky areas.
Something which can be a problem is that
the optical tube often rotates so that the
eyepiece, finderscope and the focussing
knobs are in less convenient positions.
The diagonal can be rotated to adjust the
eyepiece. However, to adjust the positions
of the finderscope and focussing knobs,
loosen the tube rings holding the optical
tube and gently rotate it. Do this when you
are going to view an area for while, but it is
inconvenient to do every time you briefly
go to a new area.
Finally, there are a few things to consider
to ensure that you are comfortable during
the viewing session. First is setting the
height of the mount above the ground by
adjusting the tripod legs. You must
consider the height that you want your
eyepiece to be, and if possible plan on
sitting on a comfortable chair or stool. Very
long optical tubes need to be mounted
Telescope pointing at the Zenith
Fig.r
higher or you will end up crouching or lying
on the ground when looking at objects
near the zenith. On the other hand, a short
optical tube can be mounted lower so that
there is less movement due to vibration
sources, such as wind. This is something
that should be decided before going
through the effort of polar aligning the
mount.
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