SynScan AZ Backlash

For those who need help choosing a setup or want further advice on how to improve their own setup
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bbones
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SynScan AZ Backlash

Post by bbones » Sat Dec 15, 2012 1:56 pm

Has anyone had any experience in changing the Backlash settings on a SynScan AZ GOTO. The manual explains what to do but does not explain how to work out the current backlash between the gears?

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Bill

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rwilkinson
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Re: SynScan AZ Backlash

Post by rwilkinson » Sat Dec 15, 2012 4:51 pm

This is what the Celestron AGT manual has to say on the subject:
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.
The process will probably be very similar for your Synta mount?
But it sounds like a long job! :(

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bbones
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Re: SynScan AZ Backlash

Post by bbones » Sun Dec 16, 2012 11:26 am

It's worth a try as come times it can be annoying when pressing the button and nothing happen

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Re: SynScan AZ Backlash

Post by bbones » Wed Dec 19, 2012 11:15 am

Well I had a go, not the results I expected. I followed the instructions from the latest manual

If there is backlash in the motor driving system, users might see a lag when moving an object in the FOV of the telescope with the direction keys. The SynScan hand controller can control the mount to slew with higher speeds for a specific amount of distance when the user revers¬es the moving direction of an axis with opposite direction keys. Such backlash compensation function helps the user get faster response from the mount.
1. Access the menu “SETUP\Backlash” and press the ENTER key.
2. The screen will display “Azm = XoXX’XX” ” or “RA = XoXX’XX” ”. Use the Left/Right keys to move the cursor and use the numeric keys to fill in a number at the cursor position to input the amount of backlash in the azimuth axis or the R.A. axis. Press the ENTER key to finish the input and proceed to the next step.
3. The screen will display “Alt = XoXX’XX” ” or “Dec = XoXX’XX” ”. Fill in the amount of backlash

Note: Set the backlash value to 0 for an axis to disable backlash compensation for that axis.


However it did noting for the Backlash all it did was increase the over run of the motors once I had let go of the cursor buttons

Strange....

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