Celestron CGEM II Mode D'emploi page 15

Note: East/West Filtering – In order to ensure the best
possible full-sky pointing accuracy, your computerized
mount automatically filters and chooses its initial
alignment stars so that the first two alignment stars
are located on one side of the Meridian and any
calibration stars are on the opposite side of the
Meridian, as indicated by the "W" or "E" displayed in
the upper-right corner of the LCD East/West filtering
can be changed simply by pressing the MENU button
at any time during the alignment process
Tips for adding calibration stars:
• Although for casual observing it is not necessary to add
calibration stars, it is recommended that you add as many
as three calibration stars for optimal point accuracy
• Choosing calibration stars that are near the celestial
equator offer the better results than stars near the
celestial poles
• Although it is not necessary to use calibration stars if the
telescope mount has not been moved since its original
alignment/calibration, it may be necessary to recalibrate
the telescope if the optical tube has been removed for any
reason
Note: Meridian – The Meridian is an imaginary line in the
sky that starts at the North celestial pole and ends at the
South celestial pole and passes through the zenith If you are
facing south, the meridian starts from your Southern horizon
and passes directly overhead to the North celestial pole
For safety purposes, the Sun will not be displayed in any of
the hand control's customer object lists unless it is enabled
from the Utilities Menu To allow the Sun to be displayed on
the hand control, do the following:
1 Press the BACK button until the display reads
"CGEM II Ready"
2 Press the MENU button and use the Up and Down keys
to select the Utilities menu Press ENTER
3 Use the UP and Down keys to select Sun Menu and
press ENTER
4 Press ENTER again to allow the Sun to appear on the
hand control display
The Sun can be removed from the display by using the same
procedure as above
Tip: To improve the telescope pointing accuracy, you can
use the Re-Align feature as described below
Quick-Align
Quick-Align uses all the date and time information entered at
startup to align the telescope However, instead of slewing to
the alignment stars for centering and alignment, the telescope
bypasses this step and simply models the sky based on the
information given This will allow you to roughly slew to the
coordinates of bright objects like the Moon and planets and
provides the telescope with information needed to track
objects in any part of the sky (depending on accuracy of
polar alignment) Quick-Align is not meant to be used to
accurately locate small or faint deep-sky objects or to track
objects accurately for astroimaging
To use Quick-Align, simply select Quick Align from the
alignment options and press ENTER The telescope will
automatically use the entered date/time parameters to align
itself with the sky and display Alignment Successful
Note: Once a Quick-Align has been done, you can use the
Re-alignment feature (see below) to improve your
telescope's pointing accuracy
Last Alignment
The Last Alignment method will automatically recall the last
stored index positions to continue using the alignment that
was saved when the telescope was last powered down
This is a useful feature should your telescope accidentally
lose power or be powered down
Note: Just like with Quick-Align, you can use the Re-alignment
feature (see below) to improve your telescope's
pointing accuracy after using the Last Alignment
method To maintain a more accurate alignment over
a series of observing sessions, use the Hibernate
feature described later in this chapter
Re-Alignment
The mount has a re-alignment feature which allows you to
replace any of the original alignment stars with a new star or
celestial object This can be useful in several situations:
• If you are observing over a period of a few hours, you may
notice that your original two alignment stars have drifted
towards the west considerably (Remember that stars are
moving at a rate of 15° every hour) Aligning on a new star
that is in the eastern part of the sky will improve your pointing
accuracy, especially on objects in that part of the sky
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