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SkySafari 5 Plus + SkyBt + Orion XT12g + SynScan V4 = After Slewing Accurately To Object Telescope Then Slews Away By A Degree Or Two (Solution: Updated The SynScan Controller Firmware)

I have been using Sky Safari Plus 5 for Android and a SkyBT controller to control two Celestron telescopes for the last several months.  Everything works great.  However, I recently got a new telescope, an Orion XT12g, and I am experiencing a very strange behavior with SkySafari.  

I start off by turning on the telescope and entering all of the location, date and time information in the hand controller.  It has the Synscan version 4 controller.  I then do an alignment with the hand controller.  After that, I turn on the SkyBT and connect SkySafari to the telescope.  It takes three connection attempts to work, but it connects to the telescope, and the SkySafari screen shows exactly where the telescope is pointed.  So far, so good.

The weird thing is that, intermittently, when I select an object and hit "go to" on the Sky Safari screen, the telescope will slew to the object and the field of view indicator will come to rest on the object on the SkySafari screen.  But then, after pausing very briefly, the telescope slews away from the object by a degree or two, usually down in altitude, but sometimes to the left in azimuth.  The move is sudden and rapid, and is only in one direction (down or left from the object).  The view on SkySafari changes when this happens and it shows the field of view away from the selected object.  So SkySafari knows exactly where the telescope is pointed, and that it is NOT on the object that I asked it to go to.

As a test, when this happened, I entered the same object in the hand controller for the telescope, and the goto worked just fine.  So I believe this is a SkySafari problem.  

On some occasions, if I hit "goto" again, on the 3rd or 5th try it will actually land on the object and stay there.  Other times, it just repeats the same behavior over and over again and I have to move the telescope with the directional buttons on the SkySafari screen to get back to the object.  When I do this, the object is there (in other words, the view on the SkySafari screen is in agreement with what the telescope is actually pointing at).  

It does not do this consistently.  Sometimes the goto works perfectly fine.  The only pattern to the behavior I noticed was that it seemed to occur more with objects closer to the north celestial pole (Perseus, Cassiopea, etc.) and didn't happen with objects farther south (Orion, Taurus, etc.).  

Any assistance you could provide in resolving this problem would be greatly appreciated.  

Thanks,

Chris

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10 comments

  • 0
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    Bill Tschumy

    Chris,

    Let me talk to the guy that handles the scope control code to see if he has any ideas.  To be honest, this doesn't sound like something we could be doing.

    Just because it is working from the hand controller doesn't necessarily mean it is a SkySafari problem (although it could be).  The firmware in the HC often takes a different path when the command is given from an external program.  So the bug could be i the HC firmware.

    Stay tuned....

  • 0
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    Chris Willis

    Bill, thanks for responding and looking into this.  And let me know if you think it would be helpful to use a different telescope designation in the app (I am using the Orion XTg/XXg option now, but maybe I could use "Synscan Skywatcher" or something else).  Or if you want me to create a log file the next time I use the telescope (I did not create one the other night when this was happening).

    Chris

  • 0
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    Bill Tschumy

    Tim is perplexed by this behavior.  He asked what firmware version is in the hand controller.  Is this a brand new scope or used?

    A log file would probably be useful.  Try to keep it as short as possible.  Connect and immediately do a GoTo.  If it has the problem then disconnect and send us the file.

    Send to "bill at simcur dot com"

    You could try the SkyScan scope type.  It would be an interesting test.

     

  • 0
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    Chris Willis

    The telescope if brand new -- it shipped from Orion and arrived at my house just before Christmas.  I am traveling right now so I cannot immediately respond on the firmware version, but I will do that when I get home later this week.  Also, I think it is going to be rainy and cloudy until this weekend, so I won't be able to do further testing or a log file until then, but I will do it as soon as I can.  Thanks again for your help with this.

     

    Chris

  • 0
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    Chris Willis

    Bill, the firmware version on the hand controller is 04.37.03.  Does that have any significance to you or Tim?  

    I am still planning to try to replicate this issue and send you a log file, but it is cloudy and rainy for the next couple of days here, so it will have to wait for clearer skies.

    Chris

     

  • 0
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    Bill Tschumy

    You generally don't need to waste clear skies testing something like this.  Just do a fake star alignment indoors and have it do some GoTos.

  • 0
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    Chris Willis

    Good idea.  I will give that a try as soon as I can and I will send you the log file.

  • 0
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    Keiron Smith

    Hi Chris, 

    Was this GoTo issue ever resolved?

    Thanks!

  • 0
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    Chris Willis

    Keiron, yes.  I had been emailing with Bill about it and he suggested that I update the firmware on the Synscan hand controller.  After I did that, everything worked fine and has been working fine ever since.  

     

    Chris

     

  • 0
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    Keiron Smith

    An excellent result, Chris!  Thanks for the update!

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