Celestron NexStar SE Series Instruction Manual page 21

SCOPE SETUP: These options allow you to define the mount's operating parameters to achieve optimum performance
SETUP TIME-SITE: These options allow you to customize the NexStar display by changing time and location parameters (such as
time zone and daylight saving time)
ANTI-BACKLASH: All mechanical gears require a certain amount of backlash or play between the gears This play is
evident in the amount of time it takes for a star to move in the eyepiece when the hand control arrow
buttons are pressed when reversing directions The size of the gear backlash is constant, so with the
slower slewing rates, it will take longer for the star to move in the eyepiece when reversing directions The
NexStar SE's anti-backlash feature allows you to compensate for backlash by inputting a value that
quickly rewinds the motors just enough to eliminate the play between gears The amount of gear backlash
is different in each mount, so you will need to experiment to determine the best value for your telescope
Most mounts work best with values between 30 and 70 It is generally better to have a value that
is too small than too large If it is too large, you will see the object overshoot when you change
directions, which will make it hard to center objects in the eyepiece Gear backlash compensation
is required only for visual usage, and maybe be counterproductive when used during astrophotog-
raphy When tracking is enabled, the mount will be moving in one or both axes Pressing a direc-
tion button opposite to the direction of tracking will cause the gear backlash compensation to activate
twice: once when you push the direction button, and again when you release it and tracking resumes
To set the anti-backlash value, press the MENU button, scroll to SCOPE SETUP and press ENTER Now scroll
down to the ANTI-BACKLASH option and press ENTER Enter a value from 0-99 for both azimuth and altitude
directions and press ENTER after each one to save these values The hand control will remember these values
and use them each time you turn the telescope on until the values are changed
SLEW LIMITS: This option allows you to define how far the telescope can slew in altitude without displaying a warning message
The slew limits prevent the telescope tube from slewing to an object below the horizon and can be customized to
suit your equipment setup If you are using a large eyepiece, 2" diagonal, or camera on the rear of the telescope, you
may need to adjust the slew limits to prevent the rear accessories from striking the base of the telescope mount
For example, if you would like to slew to an object that is close to the zenith but you have a large camera attached
that prevents the telescope from pointing straight up, you can set the maximum altitude to 80 or 85 degrees to
prevent the tube from ever pointing straight up and the camera from striking your mount
FILTER LIMITS: When an alignment is complete, the hand controller automatically knows which celestial objects are above the
horizon As a result, when scrolling through the database lists (or selecting the Tour function), the NexStar 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 +20º This will ensure that the hand control only displays objects that are higher
in altitude than 20º
Observing Tip: If you want to explore the complete database, set the maximum altitude limit to 90º and
DIRECTION BUTTONS: The direction a star moves in the eyepiece varies depending on the optical accessories you are using
This can create confusion when guiding on a star using an off-axis guider versus a straight through guide
scope To compensate for this, the direction of the drive control arrow buttons can be changed To reverse
the direction arrow button logic of the hand control, press the MENU button and scroll to SCOPE SET-UP
and press ENTER Scroll to DIRECTION BUTTON and press ENTER to view options for AZM (azimuth)
Press ENTER again to display the current logic state Use the SCROLL UP or SCROLL DOWN button to
toggle between Normal and Reverse Press ENTER to accept the choice Press BACK followed by either
the SCROLL UP or SCROLL DOWN button to access the ALT (altitude) option Press ENTER, then use
either SCROLL button to select the desired logic state Press ENTER to accept the choice The Direction
buttons will only change the eyepiece rates (rate 1-6) and will not affect the slew rates (rate 7-9)
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ENGLISH
the minimum limit to -90º. This will display every object in the database lists regardless of
whether it is visible in the sky from your location.