Celestron StarSense AutoAlign Handbuch - Seite 12

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If you attempt to slew to an object that is outside

of your slew limits, a warning message will appear

to confirm that you want to proceed with slewing .

Default slew limits are 10º-70º .

• R.A. Limits (For equatorial mounts only):

Sets the limits that the telescope can slew

or track in Right Ascension (R .A .) before

stopping . The slew limits are represented in

degrees and by default set to 0°, the position

of the telescope when the counterweight bar

is extended out horizontally . However, the slew

limits can be customized depending on your

needs . For example, if you are using CCD

imaging equipment that has cables that are not

long enough to move with the telescope as it

slews across the sky, you can adjust the slew

limit on the side of the mount that is restricted

by the cables, and command the mount to

stop slewing before it reaches this point . To

set the R .A . slew limit select the following:

- R.A. East Limit: Enter a number between

+40° to -20° to define the slew limit when

the tube is on the east side of the mount .

- R.A. West Limit: Enter a number between

+40° to -20° to define the slew limit when

the tube is on the west side of the mount .

- Disable Limits: Disables any pre-defined

values that have been entered and allows

the mount to track the maximum amount

pass the Meridian (i .e ., -20° on both sides) .

If you are imaging an object across the

Meridian, Disable Limits allows the mount

to continue tracking until the mechanical

limit of your mount is reached .

GoTo Approach: Lets you define the direction

that the telescope will approach when slewing to

an object . This allows you to minimize the effects

of backlash when slewing from object to object .

Just like with Direction Buttons, setting GoTo

Approach to positive will make the telescope

approach an object from the same direction as

tracking (west) for azimuth and counterclockwise

in declination . Declination GoTo approach will only

apply while the telescope tube is on one side of the

Meridian . Once the tube passes over to the other

side of the Meridian, the GoTo approach will need

to be reversed .

To change the GoTo approach direction, simply

choose GoTo Approach from the Scope Setup

menu, select either Altitude or Azimuth approach,

choose positive or negative and press ENTER .

Guide Rates: Sets the R . A . and Dec autoguide

rate to a percentage of sidereal speed, from 0%

to 99% . This is helpful when calibrating your

telescope to a CCD autoguider for long exposure

astroimaging . Note: Most autoguiders work best

between 50% to 99% .

Direction Buttons: The direction a star moves in

the eyepiece varies depending on the accessories

being used . This feature changes the direction that

the star moves in the eyepiece when a particular

arrow button is pressed . To reverse the logic of the

direction buttons, press the ENTER once to select

Azm (Azimuth), and twice to select Alt (Altitude),

then scroll UP/DOWN to toggle Normal or

Reverse . Directions will only be reversed for

motor speeds 1-6 .

Rates 1-6 match the direction you would normally

see in the eyepiece when used with a telescope

equipped with a 90º mirror star diagonal . Pressing

LEFT corresponds to the star moving left in the

eyepiece .

Rates 7-9 match the direction you would normally

see in a StarPointer finder, other non-magnifying

finder, or correct-orientation optical finder .

Backlash Compensation: All mechanical gears

have a certain amount of backlash or play between

the gears . The Backlash Compensation feature

rewinds the motors just enough to eliminate the

play between gears . The amount of compensation

keep a guide star centered in the eyepiece . PEC

needed depends on the slewing rate selected;

is designed to improve imaging quality by reducing

the slower the slewing rate the longer it will take

the amplitude of the worm errors .

to observe the star appear to move in the eyepiece

due to backlash . There are two numerical values for

Refer to your telescope instruction manual for

each axis, positive and negative:

details about Periodic Error Correction .

- Positive is the amount of compensation applied

when you press the button in order to get the

Set Axis Position References the alignment if the

gears moving quickly without a long pause .

clutches are disengaged . For instance, you might

use this feature if you needed to rebalance the

- Negative is the amount of compensation

mount after having completed an alignment . To set

applied when you release the button, winding

the mount position, simply slew to a bright star in

the motors back in the other direction to

the named star list and select Set Axis Position .

resume tracking .

The hand control will sync on the star by asking

To adjust, press ENTER . While viewing an object in

you to center the star in the eyepiece and pressing

the eyepiece, observe the responsiveness of each of

the Align button . Once synced on the star, you are

the four direction buttons . Note which directions you

free to manually move the mount in both axes in

see a pause in the star movement after the button

order to rebalance . When you are ready to slew the

has been pressed . Working one axis at a time, adjust

telescope to your next object, manually return the

the backlash settings high enough to cause imme-

tube to the same bright star and carefully center it

diate movement without resulting in a pronounced

in the eyepiece . Using this tool will invalidate the

jump when pressing or releasing the button . Now,

PEC index .

enter the same values for both positive and negative

Home Position: Some telescopes have index

directions . If you notice a jump when releasing the

marks or switch positions . Home Position will return

button but setting the values lower results in a pause

the telescope to this location .

when pressing the button, use the higher value for

positive, but use the lower value for negative . The

Hibernate: Hibernate allows the telescope to be

telescope will remember these values and use them

completely powered down and retain its alignment

each time it is turned on until they are changed .

when turned back on . This not only saves power,

but is ideal for those that have their telescope

Custom Rate 9: Customizes the speed at which

permanently mounted or leave their telescope in

the mount slews to a target . Press ENTER to view

one location for long periods of time . To place your

the current rate and highest possible rate . The value

telescope in Hibernate mode:

is displayed in degrees per second . Press ENTER

to get to the value you want to edit and enter the

1. Select Hibernate from the Telescope Menu .

desired value . Then press ENTER again to confirm .

2. Move the telescope to a desired position and

PEC (Periodic Error Correction for Equatorial

press ENTER .

Mounts): Periodic Error Correction, or PEC for

3. Power off the telescope . Remember to never

short, is a system built into some telescope mounts

move your telescope while in Hibernate mode .

that improves the tracking accuracy of the drive by

reducing the number of user corrections needed to

Once the telescope is powered on again, the