Get Ra/Dec; Goto R.a/Dec; Scope Setup Features; Setup Time-Site - Celestron NexStar 8i Instruction Manual

To replace the contents of any of the user defined objects, simply save a new object using one of the existing
identification numbers; NexStar will replace the previous user defined object with the current one.

Get RA/DEC

Goto R.A/ Dec
S c o p e S e t
S c o p e S e t

Setup Time-Site

changing time and location parameters (such as time zone and daylight savings).

Anti-backlash

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 NexStar's anti-backlash features allows the user to
compensate for backlash by inputting a value which quickly rewinds the motors just
enough to reduce 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. Therefore, the
compensation will have to be set higher. You will need to experiment with different
values; 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. Enter a value from 0-99 for both azimuth and altitude and press ENTER
after each one to save these values. NexStar will remember these values and use
them each time it is turned on until they are changed.
Slew Limits –
displaying a warning message. By default the slew limits are set to 0º to 90º and will
only display a warning message if an object is below the horizon.
slew limits can be customized depending on your needs. For example, if you have
certain photographic accessories attached to your telescope preventing it from
pointing straight-up, you can set the maximum altitude limit to read 80º, thus
preventing the telescope from pointing to any objects that are greater than 80º in
altitude without warning.

Filter Limits

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 read +20º. This will make sure that the hand control
only displays objects that are higher in altitude than 20º. If you manually enter an
object that is below the horizon using the numeric keypad, the hand control will
display a warning message before slewing to the object.
If you want to explore the entire object database, set the maximum altitude limit to
90º and 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.
Observing
Tip!
Direction Buttons –
depending on the accessories being used. 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
- Displays the right ascension and declination for the current position of the telescope.
- Allows you to input a specific R.A. and declination and slew to it.
u p F e a t u r e s
u p F e a t u r e s
-
Allows the user to customize the NexStar display by
– All mechanical gears have a certain amount of backlash or play
Sets the limits in altitude that the telescope can slew without
– When an alignment is complete, the NexStar automatically knows
The direction a star moves in the eyepiece varies
anti-backlash
However, the
27
MENU
SCOPE SETUP
SETUP TIME-SITE
ANTI-BACKLASH
AZM POSITIVE
AZM NEGATIVE
ALT POSITIVE
ALT NEGATIVE

SLEW LIMITS

SLEW ALT MAX
SLEW ALT MIN
FILTER LIMITS
ALTMAX IN LIST
ALTMIN IN LIST

DIRECTION BUTTONS

GOTO APPROACH
AZM APPROACH
ALT APPROACH
AUTOGUIDE RATES
AZM RATE
ALT RATE
CORDWRAP
UTILITIES
GPS ON/OFF*
COMPASS *
FIND CELEST NORTH
CALIBRATE COMPASS
ALT SENSOR*
MOVE ALT SENSOR
CALIBRATE SENSOR
WEDGE ALIGN
LIGHT CONTROL
FACTORY SETTING
PRESS UNDO
PRESS "0"
VERSION
GET ALT-AZ
GOTO ATL-AZ
HIBERNATE
* Indicates features that require
the use of the optional CN16
GPS accessory