Sky-Watcher EQ2 MOUNT - Manual (Page 19)

19
Telescopes with long focal lengths often
have a "blind spot" when pointing near the
zenith, because the eyepiece-end of the
optical tube bumps into the mount's legs
(Fig. q1). To adapt for this, the optical tube
can be very carefully slipped up inside the
tube rings (Fig. q2). 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 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.
Fig.q
1.
Telescope pointing at the Zenith
2.