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  #41  
Old 29-08-2019, 11:38 PM
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Astrofriend (Lars)
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Hi Bojan,
Yes, I read about the carbon fibre that it nail down the surfaces.

Working hard here to assemble the 3D printer. Took some photos for you who find it interesting to follow:
http://www.astrofriend.eu/3d-printin...ter-setup.html

For you who have experience of 3D printing, is it a good machine? The printer didn't cost much.

Working space 230 mm diameter and 300 mm high with a cone at the top.

I start a new 3D thread later about this when I print my first adapter.

This evening I shall visit a friend with a lathe, doing some work on the pulleys.

/Lars

Last edited by Astrofriend; 30-08-2019 at 02:14 PM.
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  #42  
Old 05-09-2019, 05:33 AM
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Now at last, I can start assembling the EQ6 mount again.

I started with installing the 60 teeth timing pulleys. Some small adjustment I had to do once again, of course :-)

Here it is:
http://www.astrofriend.eu/astronomy/...ebuilding.html

/Lars
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  #43  
Old 06-09-2019, 09:54 AM
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I think 3-D printed timing pulley would work....

Please note, any PE introduced by pulley will be divided by 180 in EQ-6, and errors generated by gears will always be larger... IMO.
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  #44  
Old 16-09-2019, 01:58 AM
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Today I have assembling more items on the EQ6 mount. I have measure the needed thickness of the RA and DEC shafts shims. I also checked if the length of the timing belts are correct, amost but have to do some modifications.

Here is photo and info of todays work on the EQ6 mount:
http://www.astrofriend.eu/astronomy/...ebuilding.html

/Lars
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  #45  
Old 18-09-2019, 08:30 PM
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The last days I have test assembled the EQ6 mount, belive it or not, but after a few modifications everything looks to fit together and the timing belt when rotating it gives a fantastic smoth feeling.

See the latest here:

http://www.astrofriend.eu/astronomy/...ebuilding.html

Now I just have to unmount it clean it once more, put on grease and then assembling it again.

/Lars
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  #46  
Old 21-09-2019, 11:55 PM
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Now I have come as long that I can do the first test.

One thing I found is that the RA and DEC shaft doesn't revolve as smooth that I has thought. It's much better than earlier but still, when revolve a turn I can feel that about 1/3 it makes a little bit more resistence. And it doesn't rotate by itself, but I can easily rotate it by my finger tip. The gap between the scale ring and chassis is enough all the way around, at least 0.1 mm.

The big 6 roller bearings felt perfect to me, only resitance I could felt was the gasket. Even the two conical bearings felt ok. Didn't replace them, only the 4 small roller bearings to the worm drive.

How low is the friction in your EQ6 mount that you have regreased?

Latest:
http://www.astrofriend.eu/astronomy/...ebuilding.html

/Lars
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  #47  
Old 23-09-2019, 11:25 PM
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Now I found what happens in the mount and cause the friction.

It's only when the cluthes are open I have friction. When closed and tracking it rotates with the two other roller bearings and then it's almost no friction. Good!

Some photos from when I testing this:
http://www.astrofriend.eu/astronomy/...ebuilding.html

For me it had been better without these clutches, less complicated and more compact, save some kg also.

If I ever build my own mount it shall not have any clutches and no gearboxes. It shall have direct driven 3-phases DC motors. For the moment only a dream.

Until then I collect information:
http://www.astrofriend.eu/links/link...rivemount.html

/Lars
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  #48  
Old 25-09-2019, 10:20 PM
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Now at last, I could power up the EQ6 mount again.

Really exiting to do this first test. One important thing was to setup the EQMOD with custom gear ratios, never done it before. It looks to work with the indoors test I did.

Here it is:
http://www.astrofriend.eu/astronomy/...ebuilding.html

To my surprise the sound / noise was almost as high as before. Maybe others with standard spur gear has very high noise.

I hope we get a clear sky soon so I can do real test.

/Lars
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  #49  
Old 30-09-2019, 06:23 AM
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Lars,
The noise you hear is generated by PWM (Sawtooth waveform current, flowing in motor coils), that is why the change in sound was not significant..
However, what you will find is the significantly smoother tracking, because you removed the transfer gears, so the only potential issue for PE and un-even moving remained will be the worm and worm gear.
In case you need/want to improve that, you will have to lap it with diamond paste (available on ebay for couple of $$).
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  #50  
Old 30-09-2019, 07:10 PM
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Hi Bojan,
The noise reduction wasn't that important, my neighbours will sleep anyway. But I noticed that the old spur gears hade very lot of grease on them, maybe that damped the noise earlier and that's way it isn't that much difference.

Now I have adjusted the worm gear play and the worm driva axial play to be very tight. Indoors it woorks like a charm, but maybe problem out in the coldness later. Then I have to fine adjust it a bit.

Two new pages:
http://www.astrofriend.eu/astronomy/...ebuilding.html

On page 15 I have added a stop for the dovetail rail to fit in correct position where the DEC balance point is. It will help a lot in the cold and darkness. Very simple done but very useful.


I have now almost eliminated the play and backlash so it will be very interesting to see how it behave in reality.

/Lars
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  #51  
Old 03-10-2019, 12:53 AM
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The last night we got a clear sky and I could do some testing of the EQ6 mount with its new timing belt.

At least everything started up and it moved as it should.

But when doing auto guide calibration in PHD2 I got a varning about the orthogonality bewteen the RA axis and the DEC axis.

I also have a little strange behavior of the RA axis, it looks to rotate too fast. I compensated it with the drift compensating in EQMOD, set it to -18.

And about the most interesting, the auto guidning error ? Well, if not perfect it was below 1", the tot rms error. The drifting looks to be slow and smoth so with tweaking of the guide parameters it maybe is possible to get lower.

Here it is:
http://www.astrofriend.eu/astronomy/...ebuilding.html

Any idea why I get that high orthogonality error (more then 10 degrees) between the RA axis and the DEC axis ? Do I have to setup the new gear ratio in more places then the EQMOD setup window ?

/Lars from cold and dark Sweden
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  #52  
Old 03-10-2019, 08:06 AM
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Lars.

I wouldn't know why you have issues with EQMOD and orthogonality error, I am not using it (someone on forum should know..).
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  #53  
Old 04-10-2019, 07:05 PM
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When I had problems with that error in PHD and HEQ5 the two issues were cone error, the scope not parallel with the axis, and play in my dec axis and mount plate fixings.

Quote:
Originally Posted by Astrofriend View Post
The last night we got a clear sky and I could do some testing of the EQ6 mount with its new timing belt.

At least everything started up and it moved as it should.

But when doing auto guide calibration in PHD2 I got a varning about the orthogonality bewteen the RA axis and the DEC axis.

I also have a little strange behavior of the RA axis, it looks to rotate too fast. I compensated it with the drift compensating in EQMOD, set it to -18.

And about the most interesting, the auto guidning error ? Well, if not perfect it was below 1", the tot rms error. The drifting looks to be slow and smoth so with tweaking of the guide parameters it maybe is possible to get lower.

Here it is:
http://www.astrofriend.eu/astronomy/...ebuilding.html

Any idea why I get that high orthogonality error (more then 10 degrees) between the RA axis and the DEC axis ? Do I have to setup the new gear ratio in more places then the EQMOD setup window ?

/Lars from cold and dark Sweden
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  #54  
Old 05-10-2019, 04:50 AM
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Cone error of 10° is huge... and must be induced by software bug or some mistake with settings.

Even 1° would be too large, those mounts are mechanically much more accurate.
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  #55  
Old 05-10-2019, 05:19 PM
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Its been intersting following this reconstruction. Hope you get it sorted

Last edited by ChrisV; 06-10-2019 at 02:54 PM.
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  #56  
Old 05-10-2019, 08:15 PM
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PHD reports a orthogonality error which is a combination of many mount errors I am guessing so the 10 degrees is almost ok and not the true cone error I think. PHD still works at that I think.

When using Argonavis I discovered there is a plethora of Mount errors which it adapts for in a very complex way as it uses 10000 step encoders to give very precise pointing. Alas , PHD with poor encoders and sloppy worms on HEQ5 can not hope to compensate for these. That’s what guiders are for, adapting to poor hardware.

That is my take , but I am happy to be corrected.



Quote:
Originally Posted by bojan View Post
Cone error of 10° is huge... and must be induced by software bug or some mistake with settings.

Even 1° would be too large, those mounts are mechanically much more accurate.
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  #57  
Old 06-10-2019, 06:18 AM
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Hi,
Yes it's strange, but after some playing with the parameters it auto guided with less than 1" tot rms error. But still I want to know what cause this orthogonal error.

One thing that I don't have control over or any deep insight in is what exactly the Drift Compensation do. When I use GOTO command it stop at correct position according to the RA and DEC scales on the mount. But when tracking it does not run at correct speed until I adjust the drift compensation. I just remember something about a bug in the stepper motors driver board. Anyone else knows something about why the Drift Compensation is needed ?

Now I need a clear sky so I can continue testing the PHD2 and auto guiding.

I just say, just do this rebuilding if you find it interesting, otherwise buy a complet kit.

For me the advantage is that I learn a lot to next time I do something simular and I have learned a lot from this rebuilding.

But now I must end this project and start using the equipment. I also have my new 3D printer waiting. Two new project to start with.

1, an adapter between my angled viewer and Star Adventurer polar finder.

2, Solve my EQ6 rpoblem with adjusting the altitude polar align (living at 60 degree latitude). I think I can do it with 3D printed plastic part, at least I have to test it.

Here I collect information: http://www.astrofriend.eu/astronomy/...ebuilding.html

If I can learn how to CAD advanced drawings with threads and other things I will have a lot of things to do in the future.

I thank all people here for all the comments and tips, great help !

/Lars
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  #58  
Old 08-10-2019, 04:12 PM
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Hi,
I found a very good info about how to setup PHD2 and EQMOD. I follow it and redo the setup, what was very different was the RA / DEC Ratio, I had it earlier set to 0.3 but now increased it to 0.7 according to the reccomendations I got. I don't remember why I set it to that low value in my old setup.

Here is how I set it up as far I could come:
http://www.astrofriend.eu/astronomy/...ebuilding.html

I couldn't do any test because of clouds.

What speed ratio are you using ?

Lars
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