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CPC 1100 Lose Alignment after a few GoTo's

Celestron
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#1 Spuxie

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Posted 16 July 2020 - 08:29 AM

4 year old Celestron CPC 1100. Have always struggled with alignment issues.  Use wedge occasionally, but 90% of time Alz Az only.  I introduced Starsense 2 years ago which was also a struggle 

 

In all cases with without Starsense after alignment ( have tried them all ) and a few Go to's  The ALignment is off. Scope slews to a destination that is west of target. Target in view in Finder, way left in field,  Use Right Arrow to center and tracking is acceptable for viewing

 

Latitude from GPS almost always adjusts after alignment to about 10' greater than when started alignment. Using User align to realign but all in all spend 50% of the evening futzing with alignment issues.   

 

Some nights are good but its just a matter of time before alignment is off again.   When I see observers in rock solid alignment with very accurate tracking for hours , I know I have never experienced that.  Maybe Backlash but I always finish movement correctly. And a scope like that with backlash issues ? Not likely , I may be wrong.

 

Over the past few years my attempts at near perfection in alignment have been a research journey and thanks to Micheal Swanson for all his valuable information.  But, I still have not reached a level where astrophotography is remotely possible. Even though I have a Guidescope with Guider.  If you cant get an accurate GoTo you are dead in the water.

 

 

 



#2 KTAZ

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Posted 16 July 2020 - 08:35 AM

I know what it feels like to go through this. Having put out the bucks for GOTO, especially with a StarSense, must be really frustrating.

 

What type of power source are you using?



#3 goldtr8

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Posted 16 July 2020 - 11:37 AM

Alignments are off if not using StarSense so just use the StarSense at least that is what you are telling me when I read your post.

 

Since you want to do some AP use plate solving after a slew to center the object.   

 

Also sounds like your GPS is not getting a good lock.  There have been recent updates to HC software that fixed some bugs with the GPS.   Mine can take up to 15 minutes to get a good lock on the location.    My first GPS had issues and it was not setting time correctly and my slews were off just as you say. 

 

So check your start position & time before doing an alignment to be sure the GPS has synchronized.   Also if you are using StarSense in ALTZ mode make sure you have the right start point.   In the northern hemisphere its OTA level and pointing north its the expected position in the software.



#4 Spuxie

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Posted 16 July 2020 - 02:21 PM

Power source is New AC adapter  did have issues once with Celestron Power tank but I run a cable from the house.  It's weird on the GPS thing how it locks and the Lat Long values are dead on. Then Lat changes .  The initial alignment goes great. First slew ring nebula dead center tranks fine  second Hec Cluster fine , Third something in Cygnus. and its off   the target is in the left edge of the view its like I lost and lour on time or something and gps time looks fine.  This has happened dozens of nights ever since bought cpc 1100  starsense added to the aggravation until I beat that thing with just raw persistence.  I never ( maybe 1 in 25 ) times have had accurate Goto to and good tracking for very long in an evening .  User align never gaves me back a good result,  Save align does not even work, use hybernate but again its a crap shoot.     



#5 Spuxie

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Posted 16 July 2020 - 02:27 PM

I caught something  GoldTR8  I have ALWAYS with starsense used South  Level as my starting Position  Not North.  I thought North was appropriate for Quick Align Not Manual Auto in Northern Hem.



#6 KTAZ

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Posted 16 July 2020 - 02:51 PM

I caught something  GoldTR8  I have ALWAYS with starsense used South  Level as my starting Position  Not North.  I thought North was appropriate for Quick Align Not Manual Auto in Northern Hem.

Well that should most definately solve your problem.



#7 Michael_Swanson

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Posted 17 July 2020 - 12:27 AM

It sounds like your GPS receiver is bad.  Easiest way to test that is to turn off GPS in the hand control menu and manually enter location, date and time info for a few sessions.  

 

Best regards,
Mike Swanson
https://www.NexStarSite.com


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#8 mclewis1

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Posted 17 July 2020 - 12:49 PM

I would also do a Factory Settings reset of the hand controller (and re verify that the GPS is indeed OFF) and then enter your local data and do a few good initial alignments and see if that drift in pointing accuracy has gone.

 

I'm really curious how strange GPS behaviour could affect the pointing accuracy over time, but anytime there's a poorly behaving device in the NexStar world (GPS, WiFi, etc.) there is the possibility of corrupted data on the internal bus, and while rare that can cause all sorts of strange mount behavior.



#9 Spuxie

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Posted 17 July 2020 - 01:06 PM

Michael

Do you agree that with starsense manual align that start  position needs to be North Level    
out of convenience I have always used south 

 

south or north the accuracy of that initial direction ,  how critical is that.  



#10 Spuxie

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Posted 17 July 2020 - 03:17 PM

It sounds like your GPS receiver is bad.  Easiest way to test that is to turn off GPS in the hand control menu and manually enter location, date and time info for a few sessions.  

 

Best regards,
Mike Swanson
https://www.NexStarSite.com

Michael

Do you agree that with starsense manual align that start  position needs to be North Level ?  
out of convenience I have always used south.

and

south or north the accuracy of that initial direction ,  how critical is that.



#11 Michael_Swanson

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Posted 19 July 2020 - 08:41 PM

It does not matter at all whether you point North or any other direction.  It just needs to be the same each and every time.

 

Best regards,
Mike Swanson
https://www.NexStarSite.com




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