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Mount Rotation Problem Only on Wedge

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#1 HeliAv8r

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Posted 12 September 2019 - 03:41 PM

I have a Nexstar 8SE (10 months old) and a new Wedge.  When mounted on the wedge set for 33.5 latitude (56.5 deg tilt), the mount will only rotate about 240 degrees. When I put it flat on the ground or on the tripod without the wedge, it goes round and round with no issue.  I've checked and cleared the cord wrap setting but I would expect it would give the same result when flat even if the cord wrap stop was enabled...and it wouldn't be a 120 deg gap.  Also, the motor sounds like it is straining when on the wedge but sounds OK when flat.

 

Do I need to send it in for warranty repair?  Or is this expected?  Perhaps I missed a setting somewhere.

 

Thoughts?  

 

To clarify, the scope can move in the 'Green' area only.  It points a little to the left at the top and will point to the ground and a little past.  It will not enter the 'Red' area.  

 

Thanks,

Dave

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#2 photoracer18

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Posted 12 September 2019 - 04:27 PM

Make sure none of your three base screws used on the wedge are too long. I assume you are using the three captured bolts  on top of the tripod when using it flat.



#3 HeliAv8r

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Posted 12 September 2019 - 05:46 PM

UPDATE: On the wedge, it stopped moving altogether, then the scope fell (rotated) to the bottom; the gears failed to hold it.  I called Celestron and they had me power up and try to move left & right with it flat on the floor.  It was jittery, moved a little, then stopped, then moved, etc...

 

It's now boxed up and ready to send in to repair.  Hopefully I will not take too long.

 

Thanks,

Dave



#4 SkipW

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Posted 12 September 2019 - 09:05 PM

Maybe the initial problem is a balance issue?



#5 Michael_Swanson

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Posted 12 September 2019 - 09:25 PM

Sounds like the big gear on the azimuth was not actually attached to the base.  I recall one incident several years ago where the factory forgot to install the screws that hold that gear in place.

 

Best regards,
Mike Swanson
Author of "The NexStar Users Guide II"
Author of "The NexStar Users Guide"
Author of "NexStar Observer List"
https://www.nexstarsite.com



#6 speedster

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Posted 12 September 2019 - 09:44 PM

The captive bolts in the wedge, the ones that screw into the SE base, are about 1/16" too long and limit RA travel.  This seems pretty well known but Celestron seems silent on it.  They need to fix the problem but don't even offer a warning to new buyers.  You can split a stiff fiber washer and slip it over the bolt and the problem will go away.  Sorry it happened to you.



#7 Greyhaven

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Posted 14 September 2019 - 07:30 AM

If it is an issue with the 3 mounting bolts contacting the gear the problem is not with your Celestron mount. When you modify the mount configuration you're responsible for the results. I'm not sure if your mount has brass or plastic (nylon) spur gears but it is quite possible that these took the brunt of the damage. This issue has been documented many times on this forum.

Grey



#8 HeliAv8r

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Posted 14 September 2019 - 09:03 PM

Thanks everyone.  I don't think it is an issue with the bolts, the issue was happening when the mount was sitting on the floor.  Perhaps the bolts caused it initially.  In any case, it has been sent in to Celestron for repair.

 

Thanks for all the input.  When I get it back, I will add some washers if I mount it on the wedge again....to be honest, I'm thinking of getting a new mount for AP (beginner AP).  And will not use the wedge at all.  I'll keep the stock Alt/Az mount for visual & star parties.

 

Dave


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#9 HeliAv8r

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Posted 16 September 2019 - 12:34 PM

UPDATE:

Celestron Tech Support has been AWESOME!

 

I called them on 9/12 in the afternoon, they diagnosed and provided an RMA; I dropped it off at UPS that evening.

They emailed me to let me know they received on 9/13, Friday.

Today, 9/16, ONE business day later, I received an email saying they've replaced the AZM motor, flashed the firmware, tested it, made adjustments, tested again (all functions) and will be sending it back shortly.

 

I realize that other repairs may take longer depending on what is wrong but I gotta say, I'm pretty impressed.

 

I love how they were in constant communication on the status of my repair and by the sheer speed it was done.

 

I probably should have waited until I received it to post but I was so surprised that I had to share.

 

Dave



#10 tmyers

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Posted 17 December 2019 - 07:58 AM

Dave,

 

Do you have an update on this? I am looking at a great deal on an HD Pro Wedge for my 8SE , but have read that it i not advisable to do this because of the of the geometry issues with a single arm mount on the heavier 8SE OTA.

 

Anyone else have experiences with this good or bad?



#11 HeliAv8r

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Posted 17 December 2019 - 10:57 AM

Hi tmyers,

 

Celestron service was fantastic!  I received my repaired mount quickly and it has been working great ever since.  I must say though that I decided not to use the wedge with it.  I took this as an upgrade opportunity and sold my wedge and bought an AVX instead which is what I'll use for my entry into imaging.  My Nexstar mount is reserved for outreach or home visual only.  My understanding is that the stock Nexstar mount is capable of supporting 12 lbs.  The 8SE OTA is 12 lbs and if you add a camera & guide scope you're probably pushing the limits.  Add to that the angle of the wedge and it seemed to me that it might not be the best fit for imaging with that OTA; perhaps a 6SE might work, or some other, much lighter OTA. That's my two cents anyway.  But as far as Celestron service goes, they knew I had the mount with an 8SE on a wedge and they repaired it under warranty, and quickly at that. 

 

Hope that helps,

 

Dave


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#12 Noah4x4

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Posted 17 December 2019 - 11:04 AM

Dave,

 

Do you have an update on this? I am looking at a great deal on an HD Pro Wedge for my 8SE , but have read that it i not advisable to do this because of the of the geometry issues with a single arm mount on the heavier 8SE OTA.

 

Anyone else have experiences with this good or bad?

I found a Celestron (Evolution) wedge to be an expensive infernal instrument of torture. For a year there was a 'bug' in the Starsense ASPA routine that Celestron initially didn't recognise (now fixed, but you need a CFM update if your Starsense HC software is earlier than January 2018). Even though Starsense makes Polar alignment on a wedge easier than if doing a regular Nexstar + ASPA, to adjust the wedge knobs you need arms as long as an orang-utan, the bendy talents of a contortionist and the additional 15lbs of weight eventually crippled my sciatica. I also had repeated problems with my camera and power cables fouling on the wedge despite aggressive cordwrap settings.  My advice is if you want to polar align then buy a GEM mount (as did Dave!) or buy Hyperstar (like me) and dispense with the need for any Polar Alignment, or auto- guiding etc. Both routes much easier than a wedge.


Edited by Noah4x4, 17 December 2019 - 11:09 AM.


#13 tmyers

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Posted 17 December 2019 - 02:53 PM

I had a chance to purchase one here from the classifieds for $200, but after reading multiple comments  decided against it. Thanks for your input.




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