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.