EQ6-R owners club

[mikey2000]

I also did the Dec backlash adjustment.  It took two attempts to nail it.  The first attempt was tricky as I didn’t really understand what was going on and I didn’t make the adjustment at the tightest part of the full rotation so it ended up binding when rotating through that part. (Horrible, scary noise from the motor!)

 

the second attempt went much better!

before the adjustment, you could feel the Dec backlash by hand-moving the mount. Afterwards, it’s imperceptible.

 

i still had a few awkward Dec issues guiding the other night but the scope was pointing directly vertically upwards and I understand that this is the trickiest part to aim at as far as Dec is concerned.  

 

[Greg Shaw]

Hi Mikey

My scope is also pointing directly up as well for the target I'm getting so this is probably why I'm seeing it more now too.

Just so I understand with this adjustment at the tightest part.

Do I first test the Dec by rocking the scope to see the backlash. Then keep on testing this by rotating around the Dec. Once I find the best spot (where the backlash is the lowest) I perform the adjustment and then test again in all other parts of the Dec rotation to make sure the backlash is gone?

Edited September 20, 2020 by Greg Shaw

[mikey2000]

That’s what I did on my successful attempt.  Beware, the adjustments on each grub screw are very powerful for even a tiny (eg) 1/8th of a turn.

 

at the end of the job, it backlash should be minimised at the tightest spot and mostly gone everywhere else.   I suppose, even for this quite expensive mount, the internals aren’t quite accurately engineered - maybe this is what you get when you spend even more £££...

 

i also had my scope/camera attached when making the adjustment.  I don’t know if that is necessary or not...

[discardedastro]

3 hours ago, mikey2000 said:

That’s what I did on my successful attempt.  Beware, the adjustments on each grub screw are very powerful for even a tiny (eg) 1/8th of a turn.

at the end of the job, it backlash should be minimised at the tightest spot and mostly gone everywhere else.   I suppose, even for this quite expensive mount, the internals aren’t quite accurately engineered - maybe this is what you get when you spend even more £££...

+1 to being super careful with the adjustments. Keeping track of what you've done is also really important I found - I marked each screw with a number and put a reference mark on the side for rotational measurement so I could write it all down.

I did my adjustment without the scope attached - seemed easier and it appears to have worked well - but scope-on is probably going to give a better result owing to it being under "correct" mechanical load at that point.

Any non-direct-drive mount will suffer from mechanical tolerances not being 100% and thus some backlash - more expensive stuff like the GM1000 has tighter tolerances but you're still trying to make two gearing surfaces be perfectly in contact in something made up of different materials, changing temperatures, etc. Stuff like the Mesu or ASA mounts which are direct-drive or friction drive (i.e. there's no potential for functional "slop" in mechanical interfaces beyond the motor itself) naturally has effectively no backlash (or at least not in the mechanics of it all) but you're 3-5 times the cost of the EQ6-R at that point.

[Robny]

Hi All

Had this mount for a few months not, but due to varies reasons only used it less than a handful of times....

I noticed a chirping/resonance sound coming from the mount when slewing to targets and homing at high speed I heard it from new but thought it was just the way it was, however - since seeing other peoples videos I've not hear others do this so now wondering of something if wrong with the mount or something needs adjusting.  It does it on both RA and DEC, it is correctly balanced and axis move smooth and easy when clutched disengaged.

Please can someone have a look at the attached and let me know what your thoughts are?

Cheers

Rob

 

[Greg Shaw]

It does sounds like the gears could be on the edge of binding.

When I was adjusting my mount yesterday I heard that sound soon before the the gears bound. Does it make that sound throughout the rotation or just at certain points.

I have heard the the belts can also need tightening so maybe the sound is belt slippage?

Edited September 21, 2020 by Greg Shaw

[mikey2000]

Mine made a nasty noise last night, sort of similar to the above.  It turned out it was the eyepiece tray vibrating.

 

did you try to see if the noise comes and goes at different slew rates?

[Greg Shaw]

So I had a go at removing the backlash on my mount yesterday.

When I tested the dec backlash at different locations I could really feel it. I also see what you mean about the sensitivity of the screws. I did a 1/4 turn for my first attempt and the gears binded after 1-2 seconds

A few adjustments and a test with the guiding assistant gave me the screen shot below, which is big difference from what I was getting. Would you carry on and see if it could be improved further?

Also once the play in the dec was removed I noticed a small bit in the RA but wasn't sure If I should attempt to sort that as well.

The whole 2 1/2 hours of guiding was really good 0.8-0.6. It did spike early on but never saw it again through the session so not sure what it was

[Robny]

21 minutes ago, mikey2000 said:

Mine made a nasty noise last night, sort of similar to the above.  It turned out it was the eyepiece tray vibrating.

 

did you try to see if the noise comes and goes at different slew rates?

 

29 minutes ago, Greg Shaw said:

It does sounds like the gears could be on the edge of binding.

When I was adjusting my mount yesterday I heard that sound soon before the the gears bound. Does it make that sound throughout the rotation or just at certain points.

I have heard the the belts can also need tightening so maybe the sound is belt slippage?

Thanks for the responses, I did think about the belts after I posted the video, but I thought they may have been too tight .making the motor struggle.  It does do it pretty much through the full rotation with the odd spots of what I would call a normal noise.

The noise does dissipate when I slow the slew rate.  

I also sent an email to the retailer I purchased it from and they have forwarded the video to one of the skywatcher technicians?

Rob

[discardedastro]

3 hours ago, Greg Shaw said:

So I had a go at removing the backlash on my mount yesterday.

When I tested the dec backlash at different locations I could really feel it. I also see what you mean about the sensitivity of the screws. I did a 1/4 turn for my first attempt and the gears binded after 1-2 seconds

A few adjustments and a test with the guiding assistant gave me the screen shot below, which is big difference from what I was getting. Would you carry on and see if it could be improved further?

Also once the play in the dec was removed I noticed a small bit in the RA but wasn't sure If I should attempt to sort that as well.

The whole 2 1/2 hours of guiding was really good 0.8-0.6. It did spike early on but never saw it again through the session so not sure what it was

That's definitely much better - I'd probably have another go and see if you can improve things, and definitely look repeat the same with the RA. But if you're guiding at 0.7" RMS that's widely accepted as being the limit of good guiding with this mount, so could consider that "done"! How much backlash will affect you is largely a function of how aggressive your guiding has to be - if you nudge PHD2 a bit towards avoiding direction switches (i.e. use the ResistSwitch algorithm and adjust a bit) then you can reduce backlash impact a little. But RA is generally going to be doing some back-and-forth so is worth making sure it's good and tight.

[mikey2000]

Regarding RA backlash, I wouldn’t bother. Just make sure your mount counterweights are set to make the whole rig slight “east heavy” then the RA motor is always lifting against weight.   A change of direction in RA guiding is then less an actual change but more of a slowing down while the earth rotation catches up.  Hence the desire to set guide correction speed to 0.5x - RA is then only ever running in one direction, just at different speeds.  So therefore no need to worry about backlash 🙂

[Greg Shaw]

Hi Guys

I’ve been chasing my tail the past few clear nights to try and sort my backlash out on my mount I am quite lost.

Initially I made another adjustment and then used the PHD2 guide assistant to calculate the backlash. It went up rather than down which confused me as if I went the other way it would introduce backlash that I could feel in the mount. But I went along with it and adjusted the other way and retested. I was able to get it down to 800ms great. I then set of to find my target and guide.

The guiding was all over the place. Looking back at the guide assistant it said my polar alignment was off even though I had excellent in SharpCap. This was when I realised I had movement in my mount. With everything locked I could move it side to side but a good few mm using the handle so could easily knock off the alignment. I couldn’t figure out what was wrong and packed up for the night.

Yesterday I searched through and read some posts on here about adding washers and pieces of plastic to remove any play. I then checked my mount over and saw that the eyepiece tray wasn’t fully tightened, as soon as I did that the play had gone...great!

I then checked the backlash in the Dec with my hands and as I suspected I could really feel it and I should seeing I was undoing the work I had done previously. So I set out to remove what I could feel and checked for any gear binding. I didn’t get and binding but I did notice that sometimes it would stop and I would have the press the button on the hand controller again to get it to move, not sure it that’s a cause of my adjustments?

last night I slewed to my target and then set up the guiding and then went through the assistant again. The back lash was back in the 4000ms so I turned everything off adjusted the correct way turned everything on and retested I got it back to 1800ms. Then the clouds came so I had to wait a few hours for them to clear.

Around midnight they cleared so I chose a different target Bode’s Galaxy as the original one was getting closer to the equator and light pollution I then told PHD2 to calibrate. I got a warning I had never seen before about being to far away from the north and I should be calibrating between 20 and -20 degrees. This threw me because I thought calibrating near the target was best. After reading lots of post this morning I have seen that if you use the ST4 cable that applies but if your using ASCOM like I am then there is no need to and I should be calibrating like this

I’m not too sure how to find the celestial equator or the celestial meridian I guess I have been lucky in the last few weeks with my locations. I had a look on my mobile Stellarium app but I can’t figure out where the best location is?

Also when I’m checking my mount over after modifying the Dec backlash should I also do this at this optimum calibration location?

Is there a way to check the backlash with software during the day or do I need to be tracking a star to do it?

Hope you can help guys, I feel I have fallen down the rabbit hole.

 

 

[Greg Shaw]

I've had a look at Stellarium on my desktop rather than using the phone and if I move round so I am facing the south I think I have found the recommended area. 

Is the area I've highlighted in Red correct?

[discardedastro]

Open the view settings (F4) in Stellarium, look under Markings, and you'll find options for the equator and meridian - they're not visible by default.

[Greg Shaw]

22 minutes ago, discardedastro said:

Open the view settings (F4) in Stellarium, look under Markings, and you'll find options for the equator and meridian - they're not visible by default.

Brilliant thanks. So it looks like I need to try and find objects in the south to set up the calibration. I have been facing the north up until now and have my workshop behind me which gives some additional protection from the elements.

 

[Pryce]

Sigh... Just got word my EQ6-R is delayed yet another 3 weeks at least..  Been waiting since mid august now and it's killing me! 

I'm itching to get started!!

[mikey2000]

!!! that's a long wait!!!  Although, where I live, it has been cloudy since mid august.  I wonder, if your mount arrives, perhaps the clouds will shift to Norway, in true astronomy fashion.  

But seriously, the wait will be worth it - I also stepped from an EQ3-2 to a 6R.   Use the waiting time for weight training 🙂

[discardedastro]

I've been going slightly mad trying to get my mount setup in a new home, around 20 feet from where it previously was, with a new guide camera (same guide scope).

My Polemaster unfortunately is limited to the Android client as I've got no Windows PC I can drag out to use, and despite being pretty much spot on Polaris (I think!) couldn't get the template to match.

However, I then went and tried PHD2's polar drift alignment - while it took a while to settle, it did eventually get me close to aligned. I then did drift alignment. During drift alignment I noticed PHD2 was "zigzagging" a lot but it averaged out enough for me to make adjustments for a straight trendline - looked pretty good, all told.

Then I fired up an imaging session and calibrated and got some very funny graphs out:

Thought "that's odd", and tried guiding but ended up with terrible performance:

I ran a 120s exposure to see what that translated to, which got me this (at 0.5"/px):

Doing a star-cross test seems to suggest something quite fundamentally wrong with mount motion:

I'm at a bit of a loss and probably missing something obvious - there's no obvious issues with the mount motion, no noises or anything, etc, it looks like it's aligned fine... what next to troubleshoot?

[discardedastro]

Just because there's nothing more annoying than not finding out the answer - I figured this one out. The lower bolt (i.e. on the bottom of the tripod) had worked its way loose, and so in some telescope motions and positions the whole base of the mount was slewing sideways slightly, leading to the above "fun"!

I've now tightened this, gotten the Polemaster running on an old Windows tablet I had lying around, done PA with that (good to 4.5 arcminutes, according to PHD2 guiding assistant) and I'm guiding at 1" RMS on a cloudy night, so all is right with the world again!

[Greg Shaw]

Do you mean the one which is below the eyepiece tray? I had he exact same issue which I mentioned a few posts back. It threw me off completely and started researching ways to remove slop in the mount when al I had to do was tighten the bottom bolt.

I currently have mine out imaging at the moment and have been playing around with the guiding settings. I have found it really does help to (at the meridian and celestial equator) calibrate, perform guiding assistant, adjust settings and calibrate again. I was getting around 1 RMS and then when I slewed to my target which was in the opposite side of the sky and started guiding it settled down to around 0.8

[discardedastro]

That's the one, though I've not got the eyepiece tray fitted. All happily nipped up and guiding now.

I think if I were mounting this more permanently I'd put something tacky/adhesive between the mount and tripod top to resist any slewing, or drill the bottom bolt for a rod so I could apply a bit more torque to tighten that, maybe with some blue Loctite.

I'm averaging about 0.75" at the mo, so doing OK - I did guiding assistant near the equator and adjusted accordingly. I'll drift align once I'm done futzing with the optical train and switching to OAG and get it dialled in perfectly for the rest of winter since this lives outside.

[Greg Shaw]

I actually found the eyepiece tray helped to increase the torque and would hold the top mount to the tripod better.

Wow  0.75" is great, I am planning to do a PEC because every now and again my guiding goes mental and then sorts itself out.

[tonylumley]

Hi all, just got my new EQ6R pro, so on a bit of a high! Lol 2 questions,if that's OK, is there a requirement to join this group or are all welcome and if joining required , how. 2nd and more important( to me, don't want to blow anything!) Can I plug my Sky watcher GPS into the auto guide port, many thanks Lum

[mikey2000]

All welcome!   Sorry I can’t help with your GPS question though.  

[tonylumley]

thanks  mikey anyway, probably e-mail Firstlight in the morning,