Derek Vasselin avatar

Recently had to do some maintenance to my EQ6-R Pro Mount due to guiding issues and thought I'd share for anyone who may be struggling with similar issues.

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I’m using an EQ6-R Pro with an EdgeHD 8, OAG, and ASI2600MM. Mount is about 2 years old and I've gotten it pretty dialed in. I’ve been averaging <0.5” RMS guiding all through the summer and fall. I’ve weighed my OTA and attached accessories (camera, filter wheel, etc) to about 23 lbs.

Recently I noticed the guiding would progressively worsen throughout the night. I’d start with <0.5” RMS guiding for the first 1-2 hrs with crisp images, then slowly exceed 1” guiding throughout the night and end up with lots of unusable data. I understand seeing changes through the night could play a small role, but the differences were too significant to only be that.

I figured with the cold snap, that might have something to do with it. My first suspicion was this was tightening some joints, or the grease was gumming up.

I was expecting the worst (having to break down to tune and re-grease). Fortunately the issue was much simpler.

Turns out the issue was really sticky axes (both DEC and RA). Sky-Watcher worm gear mounts seem to be overly tightened out of the factory and don't perform at their best without tuning a number of items, including this.

I had previously done this as part of my original tuning about a year ago, but I guess either time or the cold weather had tightened them back up. So this is a good reminder to check, even if you've already done it on the past!

If you're not sure how to do this, here's a video of it. Very simple: https://youtu.be/0yzFTjlpZaI?si=V_lQ3hcwdn4_3YDw

I also used this time to check the belts and backlash to make sure there weren't any other hidden issues.

After 2 full night's of imaging, I can confirm the issue is resolved.

I will probably still do a full hypertune at some point (like what Astrobloke does in his YouTube video). Maybe in another year or two. But I didn't find it necessary at this point.

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John Walsh avatar

Great info Derek! Having the same issue the last couple of nights, especially in certain scope orientations.
Did that before like yourself but will check it again.

Thanks

CS John

Derek Vasselin avatar

John Walsh · Dec 16, 2025, 07:55 PM

Great info Derek! Having the same issue the last couple of nights, especially in certain scope orientations.
Did that before like yourself but will check it again.

Thanks

CS John

Yeah I think the cold weather tightened the tolerances and forced a re-tune.

My other theory was the grease was wearing out and thickening, but seems that wasn’t the problem.

I have seen reports of imperfections in the internals as well that were improved by re-tuning or replacing bearings, pulleys and belts.

I also shifted my balance slightly east-heavy on the RA axis which is supposed to keep a slight amount of pressure on the gears and prevent bouncing between gear teeth as it rotates. At this focal length, every little tweak helps.

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