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Whilst The Rotation Of SkyWatcher Mount Declination/Altitude Axis Is Rock Solid The Celestial Declination Reported By The SynScan Varies (Drifts) With RA (Solution: Contact SkyWatcher Support)

I am trying to use SkySafari 5 and SkyFi to control my new Skywatcher EQ8. I have no issue connecting using scope type "Skywatcher Synscan".   However, following connection, the declination motor on the EQ8 is engaged at a very slow speed and continues to run while the SkyFi unit is connected.  Physically disconecting the SkyFi results in the motor stopping.  Whilst the drift in DEC is fairly slow ( ~0.1" every 3 to 5 seconds ) I of course am unable to take images.  

Are you aware of this issue?  Do you have a fix?

Thanks,

Mike

 

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8 comments

  • 0
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    Bill Tschumy

    Mike,

    We are unaware of this issue.  It would be nice if you can give us more information about it.  Does it start when you first connect to the mount?  Is it after a GoTo or a sure using the buttons?  Does moving the mount using the hand controller make it stop drifting?

    It might be good for you to collect a Scope Log while the drift is occurring. Perhaps that would shed some light on it.

    To be honest, I'd be pretty surprised if this is a SkySafari/SkyFi bug.  That code hasn't changed in a long time and We've had no other reports of this.

    You could look to see if a SkyWatcher Firmware update is available and install the update if so.  That might correct this.

  • 0
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    Mikeoday

    Thank you Bill, I will run some more tests this weekend and double check if there is a firmware update for the motor driver ( I updated the Syscan firware as soon as I got the new mount ).

    As soon as the Skyfi is connected, Skysafari shows the declination of the scope continuously changing.  Using Skysafari to move the scope in either axis does not stop the declination changing. 

    By scope log, do you mean via PHD2 or does Skysafai have the means to capture a log?

    Cheers

    Mike

  • 0
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    Bill Tschumy

    SkySafari can capture a scope log.  Go to Settings > Telescope Setup and note the "Save Log File" option at the bottom.  Enable that.  If you tap the ? and the lower right of the panel, it will bring up Help for that screen.  Near the end it talks about saving a log file and how to retrieve it.

    The only communication we are having with the scope after connecting is asking for where it is pointed about 4 times a second.  I can't see how that could cause a declination drift.

  • 0
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    Steenkh

    I too experience drifting with my SkyWatcher telescope though it never occurred to me that it might be caused by SkyFi (and it probably isn't).

    Mine is a Dobson, so it might be completely unrelated, but I am going to watch this thread carefully.

  • 0
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    Mikeoday

    Ok, I have run some tests and it looks like my issue has nothing to do with SkySafari or the SkyFi module ( sorry to be a bother ) - instead it would appear to be a 'feature' of the Syscan 4 ( firmware version 4.39.04 ).

    I do not remember this happening with my old AZ EQ6 with Synscan 3 but with the Synscan 4 the celestial declination reported by the Synscan is not a fixed offest relative to the rotation of the mount's declination axis.  That is, whilst the rotation of mounts declination/altitude axis is rock steady ( and reported so by the Synscan ) the celestial declination reported by the Synscan varies with RA.

    What I think is happening is that the Synscan hand set is attempting to correct for declination drift due to polar alignmnet error.  I assumed it did not do this.

    For my test ( without the SkyFi connected ) I timed how long it took for the reported declination to change as follows:

    - scope pointed at 0deg declination on the meridian: 0.2" per minute

    - scope pointed at 0deg declination on the horizon: 12" per minute

    If I am right this would indicate that I have a very small polar alignment error in azimuth and quite a large error in altitude.  I will try to confirm this tonight.

  • 0
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    Mikeoday

    Mmmm, not so sure about the reason now ...

    Synscan polar alignment report:  Az error: 0' 42"  El error:  10' 50"

    Accoding to an online calculator ( http://celestialwonders.com/tools/driftRateCalc.html ) this should result in drift rates of approx. 0.2" / min at meridian ( so this is ok ) but only 2.8" / min at the horizon ( or a quarter of the drift in dec shown by the Synscan ).

    I will try again to remove all polar alignment error in elevation tonight and see if it makes a difference.

  • 0
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    Mikeoday

    Ok, changing the polar alignment does change the rate of drift but in a way that is not consistent with the change in alignment error.  

    This issue is not related to SkySafari or the SkyFi unit.  I will try to contact Skywatcher for their help.

    Thanks

    Mike

  • 0
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    Bill Tschumy

    I'm glad to hear it is not a SkySafari problem.  I hope you are able to figure it out with SkyWatcher.

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