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Old 10-11-2019, 05:55 PM
Imme (Jon)
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NE6 BOOM BOOM TUNE-a.k.a Hypertune with new Rowan Astronomy Zero Backlash Worm Block

Iíve really gone off imaging lately due to what I deem pretty poor guiding. Iíve done everything I can think of to tweak the mount but it seems Iím unable to make any noticeable improvements.
My NEQ6 is a couple years old and with the chopping and changing of equipment Iíve gone from it carrying 8kg to around 14kg..... my guiding errors have increased with the weight, going from around 1rms to almost 2.
I donít see this as acceptable as an average error when imaging (although I am only running a focal length of 910mm so it probably would be ok I guess!)
Iíve been tossing up buying a new mount however I canít justify the $ís needed to upgrade to something in the high end market when I doubt my imaging gear is going to get any heavier than it is now so a step up to a greater capacity isnít needed.

So what to do....... after hours of reading and research Iíve decided to do a ďBOOM BOOM TUNEĒ.... whatís a ďBOOM BOOM TUNEĒ you ask......well itís really similar to a HYPERTUNE but from what Iíve read the term HYPERTUNE has been copyrighted so I canít call it that...... the worlds gone nuts hey....so BOOM BOOM TUNE it is!!! (PS, Iíve now copyrighted this term myself to ensure no one uses it without first paying me a fee)

Iíve purchased a Rowan Belt mood from Sidereal for backlash, although as we know this only reduces it, doesnít remove it entirely.
While looking at their site I noticed a new product I havenít seen before, a Rowan Zero backlash spring loaded setup for the RA axis.... interesting concept however researching it I can find basically no info as it seems to be a fairly new product.
Initially I left it as I thought Iíd just take the normal route and balance east heavy to soak up that leftover backlash....but thinking about it, by balancing east heavy Iím actually reducing mount performance to cover an issue with the mount.... why bother doing a BOOM BOOM TUNE ifi still need to make allowances for issues with the mount..... much better to remove to issue to begin with if I can.....so Iíve also ordered the zero backlash RA thingy-ma-jig!!! Should be interesting to see how this thing works and whether it does eliminate backlash all together

Last edited by Imme; 13-11-2019 at 05:20 AM.
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Old 10-11-2019, 06:33 PM
Startrek (Martin)
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I feel your frustration
A few suggestions -
Do you balance ďeast heavyĒ on both sides of the meridian ?
Are all your cables just hanging from the main axis yoke or tied up with a small drag loop
If you use PHD have you tried upgrading to PHD2
If you use PHD2 have you tried the PPEC algorithm in lieu of Hysteresis
If your stars are still round at 1.5 to 2.0 arc sec with long subs , why worry , in the end itís a good image your after not sub arc sec guiding

Hope others can pitch in with some suggestions too
Cheers
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Old 10-11-2019, 06:38 PM
Imme (Jon)
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Tried all the above Martin, thing is I like things to work as they should....I don’t like having to make this adjustment and that adjustment to compensate for things.
I’ve purchased the rebuild bits now and started the tear down so no looking back now..... it’s BOOM BOOM TUNE time!

Last edited by Imme; 10-11-2019 at 06:58 PM.
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Old 10-11-2019, 06:57 PM
Imme (Jon)
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Stage 1 - The tear down....

I tell ya what, these mounts are super simple to pull apart....let’s hope they go together as easy!

Few issues found during disassembly that probably didn’t help my guiding -
1. One of the delrin washers was broken. Cracked right through.
2. One of the RA Allen screws was stripped in the hole (from the factory because I haven’t touched them!).
3. While pulling the insides to pieces I noticed some grit on my fingers..... guessing it’s swarf from manufacturing or some crap from the striped thread (thread opens up into the main body)
4. Dec axis was pretty loose....well loose’ish
5. There was plenty of gear slop (not meshing properly) in the motor to middle gear.....especially on the DEC axis. The belt mod alone should fix a fairly significant issue just by replacing these gears I’d say.

Seems there was a good amount of grease in there which still seemed fairly good..... but this will all be cleaned out and replaced regardless.

Bearings seem ok but I will replace the DEC worm ones. RA don’t need replacing as the zero backlash block comes with new high quality bearings apparently. I’ve ordered some Japan made 608 bearings on eBay which I will use for the DEC.

Ive also found some PTFE sheet on eBay which I’ll cut up into a washer and use to replace the broken delrin washer......PTFE and delrin are basically the same thing so it’ll be fine.

Grease- I’ve ordered some Superlube grease to re-grease the mount. Seems that this is the go to stuff.

The rounded grub screw..... appears to be enough ‘meat’ left here to drill out and put a threaded sleeve in. Should end up stronger than original in think.

All in all I’m pretty happy to have found all the issues....it gives me a reason why the mount started acting up and in turn this gives me things to fix to make it better.
Time to clean this thing up now!

Last edited by Imme; 12-11-2019 at 07:18 AM.
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  #5  
Old 11-11-2019, 06:04 PM
Imme (Jon)
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Little more progress.....

I’ve decided that as I’m pulling this thing to pieces for what I hope to be the first and last time I may as well replace all the bearings with some good quality ones and do the job properly. I’ve ordered 8 more premium Japan built bearings today which will replace all of them.... even if it only gives me a 0.1rms improvement then why not I say. Cheap enough to buy in the scheme of things really.

I did run into another issue undoing the saddle/mount head..... another stripped out grub screw. Guess the skywatcher screws are pretty low quality items from what I can see...... drilled and then’easy-outed’ it. I think I’ll just replace all grub screw with stainless steel ones. Cheap insurance to make sure it doesn’t happen again!

I also removed the ALT setting bolts today and put a couple nylock nuts and washers on them to be used as lock nuts once set up on the pier..... probably overkill and not needed but I’m getting bored waiting for parts!

Last edited by Imme; 12-11-2019 at 10:32 AM.
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Old 12-11-2019, 06:46 AM
Pepper (Steve)
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You should get some decent results.
Really improved the tracking accuracy on my lowly eq5.
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Old 12-11-2019, 07:17 AM
Imme (Jon)
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Iím hoping it will. As I said earlier I canít justify spending $6k on a new mount when I know Iím probably never going to go heavier than the 14 kg odd Iím imaging with now.
If this rebuild gives me solid 1rms tracking Iíll be happy with that at my focal length.
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  #8  
Old 12-11-2019, 09:16 AM
Startrek (Martin)
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Jon
I bought an EQ6-R Mount last April to carry my 8Ē f5 newt and consistently guide under 1 arc sec in all conditions ( no mods , straight out of the box )
Best guiding figures around 0.65 to 0.75 arc sec error on good nights
My payload is around 15kg ( note the 3 x 5.1kg counterweights)
Mount brand new cost me $2,250.00
Great mount for the money and performs better than expected
Dithering is a joy , it just recovers in Dec so quickly
I reckon it could handle up to a 10Ē f5 and still perform ok
My 3 year old HEQ5 mount carryís my 6Ē f6 newt at 9 kg payload and I can never get under 1 arc sec , always around 1.20 to 1.30 on good nights
and dithering knocks it around so much
Thumbs up for the EQ6-R mount , after 8 months in all conditions itís proven itself each time I image
Cheers
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  #9  
Old 12-11-2019, 09:47 AM
Imme (Jon)
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EQ6-R....that has the belts. I think they really make the difference, turning a good mount into a much better one.

I did toss up upgrading to one of these however felt my time/money would be better spent tuning the mount I have. The way I see it is I'm getting the belts but also upgrading bearings, cleaning the insides and putting my own personal touch/care to it to make sure it's as perfect as I can make it rather than leaving it to some guy working in a factory somewhere who is only interested in doing a job good enough to collect his paycheck at the end of the week.

I'll be happy to get the figures you're getting although I am pushing for lower.....I don't really need lower figures but I want them! hahahahaha.
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Old 12-11-2019, 10:29 AM
Startrek (Martin)
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I agree with your idea no use wasting money but itís a shame they did bring the R out earlier
Donít get too caught up in guiding numbers as your focal length on the 130mm is only 910mm same as my 6Ē newt and I get round stars even at 1.80 arc sec error and 2 minute subs
As long as your around 1.00 arc sec error with no big variance in Dec you can easily push +5 minute subs with a focal length under 1.5 metres
Good luck with your big tune up !!
I might do a Rowan belt mod to my HEQ5 next year which should improve tracking and guiding substantially
All the best
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Old 12-11-2019, 10:33 AM
Imme (Jon)
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Quote:
Originally Posted by Startrek View Post
I agree with your idea no use wasting money but itís a shame they did bring the R out earlier
Donít get too caught up in guiding numbers as your focal length on the 130mm is only 910mm same as my 6Ē newt and I get round stars even at 1.80 arc sec error and 2 minute subs
As long as your around 1.00 arc sec error with no big variance in Dec you can easily push +5 minute subs with a focal length under 1.5 metres
Good luck with your big tune up !!
I might do a Rowan belt mod to my HEQ5 next year which should improve tracking and guiding substantially
All the best
Cheers Martin.
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Old 12-11-2019, 05:02 PM
Imme (Jon)
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Because my mount is pier mounted it’s a bit of a set and forget type setup. Once I get it polar aligned I don’t want it to move!

Quick little mod to the ALT axis tonight should make sure of that I think.

Took out the M4 grub screws, re-drilled the holes, tapped them to a M6x1 thread and put some cap screws in to keep it in position. Much sturdier than before.
The locknuts I put on yesterday now are probably not needed....but I’ll leave them for extra security as they’re not in the way of anything.

Obviously cleaned and regressed everything as well.
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Old 14-11-2019, 01:31 PM
Imme (Jon)
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RA zero backlash block arrived today.
Looks very well made as I expected from Rowan Astronomy.
Assembly instructions seem pretty straight forward and itís pretty clear to see how this thing works..... nice strong action that will keep the worm against the gear but loose enough to not cause binding.

Unfortunately Iím waiting on a few bearings before I can l put this mount back together but hoping theyíll be here tomorrow.

As mentioned in a previous post I had a rounded out thread on the DEC cover that must have occurred at the factory as Iíve never touched it. Last night I replaced this and the other three threads (as insurance) with helicoil inserts. This should/will give me me a stronger thread than original.

Home tonight to swap out the bearings I have and mount the work gear. Also need to install the pulleyís for the belt mod.
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Old 14-11-2019, 05:20 PM
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Nikolas (Nik)
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It will be interesting to see how the zero backlash bit works and if it does as I have been hanging out to see if anyone has used it.
I've done the belt mod on mine but considering this as well.
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Old 14-11-2019, 05:30 PM
Imme (Jon)
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You can get a good idea of the mechanics of it by reading the install instructions (available online).
It seems a solid bit of kit that will take up and backlash fairly easily.

I canít see why they wouldnít also be able to produce a DEC version as well now that Iíve installed it. Itís basically just a sprung worm carrier in a housing that fits the mount...... seems fairly straight forward in design if you had the tooling to do it.

......now that would be an interesting mount....a belt modded eq6 with no backlash.
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Old 14-11-2019, 07:51 PM
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RobF (Rob)
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Very interested to hear how you go Jon. Did wonder about why the chose RA to start with for the spring loading. Hope its a winner once you get back in action....
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Old 15-11-2019, 09:51 AM
Imme (Jon)
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Hope it's a winner too Rob! It can't be worse than it was in my opinion so we should be all good.

Couple of items that have popped up with the install of the new zero backlash block.

Shims - all shim measurements will need to be re-done on the RA axis as the old shims suit the old block.....if ordering the block make sure you have some shims or shim material (this is what I've done) of different thicknesses to use.

Making shims - trying to cut shims by hand resulted in a dodgy nightmare of a job. I ended up using a couple of blocks of wood and sandwiching the teflon between it before using a couple holesaws to cut the inner, then outer holes. Came up well....I used hardwood to reduce the splinter factor. Quick sand on the edges and they are as good as anything i could buy from a supplier I think.

Worm gear runout - Have people measured this or is it just a 'feels good' scenario? I've decided to be as scientific as possible with this rebuild so have spent a bit of time setting this. I currently have a measurable 0.05mm-0.08mm runout on the gears. Happy for comments by engineering types in the know re whether I should try to reduce this gap or give it a bit more play?
Note - I've took these measurements with a material temperature (fridges help here) of around 5'C which I guess is my median summer/winter imaging temp.
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Old 15-11-2019, 12:58 PM
morls (Stephen)
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Quote:
Originally Posted by Imme View Post
Grease- Iíve ordered some Superlube grease to re-grease the mount. Seems that this is the go to stuff.

I don't know superlube, but when I researched doing a strip-down of my Vixen SP mount I read somewher that Molybdenum paste was good, but expensive. I tracked down a good source at a Suzuki motorbike service centre. The part # is 99000-235140 for a 50g tube. Cost around $15.
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Old 15-11-2019, 01:00 PM
morls (Stephen)
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Can get it here too:
https://www.kessnermotorcycles.com.a...ew/99000-25140
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Old 15-11-2019, 01:47 PM
Imme (Jon)
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Originally Posted by morls View Post
I don't know superlube, but when I researched doing a strip-down of my Vixen SP mount I read somewher that Molybdenum paste was good, but expensive. I tracked down a good source at a Suzuki motorbike service centre. The part # is 99000-235140 for a 50g tube. Cost around $15.
I did look into Moly paste but swung away from it for a few reasons (this is just google based info, not learnt/known from personal experience) -
1. Over time Moly can dry out and form clumps (meaning I'd have to do another tear down to clean/re-grease
2. Moly is an assembly lube - not designed for long term lubrication. I was concerned it may lose some of its lube properties over time.

I'm sure for the low rpm's and relative minimal use our mounts get that Moly would be more than fine and probably last the lifetime of the mount......however I went Superlube for a couple of reasons - doesn't dry out or clump and it is synthetic. It might be 'snake charmer' talk but apparently it also has minute PFTE (Teflon) participles in it that will fill voids in bearings etc (microscopic size) to assist in smooth running.

In reality though I reckon butter would probably do an ok job for something that spins at 0.125rpm (worm gear while tracking sidereal)
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