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Problem with Sirius mount or Synscan

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#1 pinzmann

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Posted 13 June 2018 - 02:31 PM

I have a Sirius EQ-G mount with the goto Synscan controller. A couple of times I wasn't able to do a star alignment but the usual problem was that I imputed wrong data. So the other night I went to my dark site about 20 miles from home and set up and attempted a 3-star alignment after polar aligning. It constantly was off by 10-15 degrees. I made several attempts at this, powering off, restarting, re-entering the data, manually moving the scope. Nothing worked. It seemed to be off by the same distance and direction everytime. I triple checked my location data and time info. Nada. Finally after wasting 2 hours of imaging time, I just manually found my targets and started imaging. It tracked fine and I got good subs. I don't autoguide. 

    This is my first Goto mount and have had it for only about a year.  Is the Synscan the only controlling unit or is there something in the mount also?  Do these Synscan controllers go wacko sometimes?

   When I got back home and setup the next night, I imputed the location data for the house and everything was spot on. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



#2 rmollise

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Posted 13 June 2018 - 03:46 PM

If you're that far off following a goto alignment on three stars (good alignment stars as per the manual none close to horizon or Meridian, set to home position correctly and decent polar alignment before beginning), something is going on. It's not time and date or location or time-zone...those things only affect gotos to Solar System objects after you are aligned.

 

Possibilities? The clutches could have been slipping. Make sure you are decently balanced and the clutches firm.  Not sure what you meant by "manually moving the scope." Once it is aligned DO NOT unlock the clutches to move the scope by hand. A fully charged battery is also advisable.

 

Beyond that, it's hard to diagnose without more details...sounds like you did something you shouldn't have out at the dark site.


Edited by rmollise, 13 June 2018 - 03:48 PM.


#3 macdonjh

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Posted 13 June 2018 - 05:28 PM

Since you think you're off by fifteen degrees every time, I think you entered your time wrong.  There are a couple of possibilities:

  • you told your controller you were in PST (GMT -8) and did not tell it day light savings time is in effect (you'll be one hour behind)
  • you told your controller you were in PDT (GMP -7) and told it day light savings time is in effect also (you'll be one hour ahead)
  • you gave it some combination of wrong time zone and day light savings time that add up to a one hour error

Entering a time that's off by one hour will result in a pointing error of fifteen degrees.

 

A couple of other things to try: do a 1-star or 2-star alignment instead of 3-star (recommended to be by Orion tech-support when I had problems), reset your controller (I don't remember how to do this, check your owners' manual), update your firmware.



#4 pinzmann

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Posted 13 June 2018 - 05:30 PM

I guess I didn't explain it correctly. After polar aligning, the controller picks the first star to align, say... Vega. The mount then slews to Vega's position. Usually its visable in the finder scope. But this time it was a good 10 degrees away. So I would motor the scope to it, center it and let the controller pick the next star. It would slew to it and stop again 10-15 degrees away. After the 3rd alignment star, it would readout that alignment was poor. After that the goto would be way off when I tried to find anything. I then tried different fixes but to no avail.

 

 

 I double checked the time in every case of resetting it. I remember the readout of -8.00 and made sure DST was on. I even turned it off to see if that made a difference.


Edited by pinzmann, 13 June 2018 - 05:38 PM.


#5 macdonjh

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Posted 13 June 2018 - 05:47 PM

How is your polar alignment?  If it's off, your pointing accuracy may not be good, and you may not get an alignment model that converges (gets closer to being accurate with more stars added).

 

Have you had a chance to try any of Uncle Rod's suggestion, or the other things I suggested?  Frankly, I've tried all those suggestions and I still can't get a 3-star alignment to work, so I use 1-star and 2-star alignments.  I also use the Pointing Accuracy Enhancement function.  Uncle Rod uses EQMOD and ditches the hand controller altogether.



#6 Dave L

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Posted 13 June 2018 - 06:08 PM

I have that same problem  with my Orion Sirius.  However, the mount does not say" the alignment was poor."  To the contrary it says the alignment was successful, but like you the objects are sometimes out of the field of view.  I also have another problem and that is that the object moves very fast through the field of view.  In the past,  the  tracking had been extremely good.  Now it seems to have trouble tracking.  I spoke to Orion and the tech told me to try a polar alignment using the polar scope.  My issue with that is that in the past I never used the polar scope,  and the objects were nearly dead center in the field of view.  Tracking was excellent.  I could sometimes walk away for a half hour and find that the objet was nearly dead center in the field of view.  I would hope that other who have this problem would chime in and tell us what they did to solve the problem.



#7 pinzmann

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Posted 13 June 2018 - 07:36 PM

The thing is after I got back home and set it up the next night, it worked perfectly. I've always done 3 star alignment and never had a problem. As far as polar alignment goes, I use the polar scope and it seems to be pretty close as I can get 60 secs with a 714mm focal length scope. I don't autoguide. Also I drift align.



#8 Dave L

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Posted 13 June 2018 - 08:17 PM

Happy to hear that you had success.  I do not know how to do a drift align.  I will read up on that.  




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