#21  
Old 17-01-2016, 10:23 PM
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Atmos (Colin)
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Skies tonight weren't even worth setting up for imaging but I did test out the mount, down to 5 backlash steps so I am pretty happy with that
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  #22  
Old 17-01-2016, 10:54 PM
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codemonkey (Lee)
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Gotta be happy with that! Congrats.
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  #23  
Old 28-02-2016, 05:14 PM
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Reading some of the great tips here motivated me to operate on my (previously belt modded) NEQ6 last weekend. Tackled a few things that had been bugging me:

- large PE (probably average, but around +/- 15 arcsecs)
- RA and DEC backlash (quite a bit of give in both if moved by hand)

Very happy with the outcome. In no particularly order, things changed:

- ABEC 11 bearings in place of ceramic bearings previously used during belt mod (Tandum suggestion as per http://www.iceinspace.com.au/forum/s...highlight=abec
- Replaced a few key 6008 bearings that didn't feel super smooth
- Removed dust caps off all 6008 and worm bearings (another Tandum suggestion - apparently Tak does that in their mounts)
- Swapped RA and DEC worm and gear
- Put more tension on belts when re-assembled than previously
- Spent a lot more time working on mesh and tuning of each axis. The order suggested by "Astrobaby" seemed to work really well. (http://www.astro-baby.com/EQ6%20rebu...0alignment.htm)

Very little higher frequency noise on PEC plot and PE on the RA worm is now about +/- 7 arcsec, albeit with a blip each worm cycle or a few arcsecs that doesn't matter too much at my focal lengths (2.5 arcssec/pixel typically). No discernible looseness in DEC or RA by hand - feels much tighter with no binding. Backlash seems better, but no hard data to prove - certainly less overcorrection in Dec now.


In hindsight, things that probably helped most:

- 2nd time ever pulling it apart - better understanding this time (first time was just hoping it would slew when re-assembled! ). This time took the time to properly tune meshing.
- Lucky improvement swapping gear/worms
- getting rid of the ceramic bearings - these appeared and felt to have more "give" than traditional bearings - may not have been a good idea in the first place
- Better mesh (as above) - really thinking about the issues in post#4 from Peter as each variable was checked and tweaked.

Satisfied the NEQ6 is now performing at least as good as the HEQ5Pro has always managed, probably significantly better after a few backyard sessions this week.

Would be interested if anyone else has tried Tandum's suggestion re taking out bearing dust caps. Presumably this greatly increases the chances of future bearing contamination, but I'd be prepared to have to service more often for less vibration during tracking.

Last edited by RobF; 28-02-2016 at 05:25 PM.
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  #24  
Old 28-02-2016, 05:38 PM
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RobF (Rob)
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Also noted there is replacement kit for EQ6s now that looks great. Screw in counterweight arm with wider bore. Peter_4059 did something similar himself and seemed very happy - almost no slop.

http://www.telescope.com/Mounts-Trip...8/p/102787.uts

Saving my dollars for now however. Price seems reasonable but counterweights would need to be bored out. Bet that chrome would look snazzy though
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  #25  
Old 28-02-2016, 09:29 PM
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codemonkey (Lee)
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Good work Rob! I'll be stripping mine back down again soon to try and resolve the issue I was having in RA. Betting money the pulley has come loose again. This time I'll sort it out once and for all with some thread locker, as suggested Dave from Rowan Engineering.

I've got that aftermarket counterweight shaft, but I'm not sure how much impact it had since I think I replaced it at the same time I did the belt mod.

The counterweights from the AZ-EQ6 fit that Orion one perfectly if you happen to have any of those laying around. I bought some new ones rather than boring out existing ones.
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  #26  
Old 28-02-2016, 09:39 PM
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RobF (Rob)
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I think you end up with a better idea what guiding settings to tweak too after stripping your mount down a couple of times and looking at a few cycles of PEC. Gives you a realistic expectation of backlash, PE drift, minimum move settings etc.

Getting decent alignment and moving up min move parameters up around the RMS values seems to help too. At least until I win the lotto and by my Astrophysics dream mount
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