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Scope Setup Features
Setup Time-Site
- Allows the user to customize the telescope's display by changing time and
location parameters (such as time zone and daylight savings).
Anti-backlash
– All mechanical gears have a certain amount of backlash or play between the
gears. This play is evident by how long it takes for a star to move in the eyepiece when the
hand control arrow buttons are pressed (especially when changing directions). The Advanced
GT's anti-backlash features allows the user to compensate for backlash by inputting a value
which quickly rewinds the motors just enough to eliminate the play between gears. The
amount of compensation needed depends on the slewing rate selected; the slower the slewing
rate the longer it will take for the star to appear to move in the eyepiece. There are two values
for each axis, positive and negative. Positive is the amount of compensation applied when
you press the button, in order to get the gears moving quickly without a long pause.
Negative is the amount of compensation applied when you release the button, winding the
motors back in the other direction to resume tracking.
Normally both values should be the
same. You will need to experiment with different values (from 0-99); a value between 20
and 50 is usually best for most visual observing, whereas a higher value may be necessary for
photographic guiding.
To set the anti-backlash value, scroll down to the anti-backlash option and press ENTER.
While viewing an object in the eyepiece, observe the responsiveness of each of the four
arrow buttons. Note which directions you see a pause in the star movement after the button
has been pressed. Working one axis at a time, adjust the backlash settings high enough to
cause immediate movement without resulting in a pronounced jump when pressing or
releasing the button. Now, enter the same values for both positive and negative directions. If
you notice a jump when releasing the button, but setting the values lower results in a pause
when pressing the button, go with the higher value for positive, but use a lower value for
negative. The telescope will remember these values and use them each time it is turned on
until they are changed.
Filter Limits
– When an alignment is complete, the telescope automatically knows which
celestial objects are above the horizon. As a result, when scrolling through the database lists
(or selecting the Tour function), the hand control
will display only those objects that are known to
be above the horizon when you are observing.
You can customize the object database by
selecting altitude limits that are appropriate for
your location and situation. For example, if you
are observing from a mountainous location where
the horizon is partially obscured, you can set your
minimum altitude limit to read +20º. This will
make sure that the hand control only displays
objects that are higher in altitude than 20º.
Fig 3-3 – R.A limits- This figure shows the
full range of motion for the R.A. axis
