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Atlas EQ-G minor slop in declination-WUWT?

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#1 spongebob@55

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Posted 19 January 2013 - 12:46 AM

Hi, On my 5th time out with my new Orion Atlas EQ-G mount, I was observing the moon at high power on with my 127 triplet with a 6.7mm EP. I noticed it moved, ever so slightly in declination. If you step back and look at the OTA, you can see it move. Is there an adjustment, or could this be a bad mount, or is this 'nominal' for a GEM Altal EQ-G? Yikes.
thanks
Bob

#2 rmollise

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Posted 19 January 2013 - 10:14 AM

Moves when? When you push on it? What is moving? The dec axis or the whole works? IOW "more information." But "ever so slightly" doesn't sound like anything to get in a panic about... ;)

#3 spongebob@55

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Posted 19 January 2013 - 10:48 AM

Oh, I guess that's what happens when you write a post after being out in the cold for 4-5 hours and you're tired. Sorry, should have rad it before posting.
The dec axis moves. I first noticed it when I focused at high power, put my hand on the focuser and the image moved/telesope moved without the worm motor being engaged. Its similar to when my RV6's worm gear was not tight in its bracket and although the worm and gear was fully engaged and not turning, the worm wasn't tight and so the whole axis moved. It just seems to be the same thing, only on the dec axis.

#4 rmollise

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Posted 19 January 2013 - 12:13 PM

If it's minor, the answer is "leave it alone."

#5 astro_baby

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Posted 19 January 2013 - 03:16 PM

The Atlas/EQ6 can have some slack in the DEC axis. If its super bad you can tune it out by adjusting the worm mesh. If its fractional I would leave it be.

Messing with the worms mesh is a longish process if you hav e never done it before and you could spend a lot of time just getting back to where you are now.

#6 spongebob@55

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Posted 25 August 2014 - 02:07 PM

Well here I am, 1 year, 7 months latter and I've been living with it.  But now it seems to be getting worse.    I polar align, then use 3 star allignment, and the GO TO accuracy is great so no problems there.   about a week ago I was out with my f/l 1000mm 4" refractor and then last night I was out with my 180mm f/15 Mak.  Looking through the EP.   The object in the EP moves because of this slop.   The tripod is solid and so is the tripod/mount connection.

So this morning, I put the mount on the table top, lock both axis, extend the counter weight bar shaft, and put my fingers on the end of the counter weight bar shaft, and sure enough, you can get it to move with a slight touch left and right.

Its annoying at the EP.   I wouldn't want a long refractor on this mount with any wind, it would just bounce around.    Even the people who I show the skies to a our public outreach have commented on it.

So what can/should done?

Are there any links or discussion about how to fix this?

I'm about to get a 11" sct for this mount so I'm obsessing about it again.

Thanks for your input.....again.

 

Bob



#7 tazer

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Posted 25 August 2014 - 02:24 PM

You could send it off for a hypertuning (approx $400):

 

http://www.deepspace..._4226_8660.html

 

Or buy a kit and DIY (approx $200):

 

http://www.deepspace..._4227_8642.html

 

Or you can DIY without the kit via the guide over at the Astro-Baby site (approx $0):

 

http://www.astro-bab...p Down Home.htm

 

Section 5 is the part on worm alignment:

 

http://www.astro-bab...m alignment.htm


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#8 spongebob@55

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Posted 25 August 2014 - 07:46 PM

You could send it off for a hypertuning (approx $400):

 

http://www.deepspace..._4226_8660.html

 

Or buy a kit and DIY (approx $200):

 

http://www.deepspace..._4227_8642.html

 

Or you can DIY without the kit via the guide over at the Astro-Baby site (approx $0):

 

http://www.astro-bab...p Down Home.htm

 

Section 5 is the part on worm alignment:

 

http://www.astro-bab...m alignment.htm

 

So helpful.   Thanks very much!



#9 tclehman1969

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Posted 27 August 2014 - 04:10 AM

Well here I am, 1 year, 7 months latter and I've been living with it.  But now it seems to be getting worse.    I polar align, then use 3 star allignment, and the GO TO accuracy is great so no problems there.   about a week ago I was out with my f/l 1000mm 4" refractor and then last night I was out with my 180mm f/15 Mak.  Looking through the EP.   The object in the EP moves because of this slop.   The tripod is solid and so is the tripod/mount connection.

So this morning, I put the mount on the table top, lock both axis, extend the counter weight bar shaft, and put my fingers on the end of the counter weight bar shaft, and sure enough, you can get it to move with a slight touch left and right.

Its annoying at the EP.   I wouldn't want a long refractor on this mount with any wind, it would just bounce around.    Even the people who I show the skies to a our public outreach have commented on it.

So what can/should done?

Are there any links or discussion about how to fix this?

I'm about to get a 11" sct for this mount so I'm obsessing about it again.

Thanks for your input.....again.

 

Bob

A little confusion here. Your original post said you were experiencing movement in declination, but in this post quoted here you said you pushed on the counterweight shaft. Pushing on the counterweight shaft effects RA, not dec. so clarification here could be helpful.

 

as for the movement you experience, is it a slight amount of slack you pick up when pushing on the cw shaft, or are you able to push and push and push and it just keeps moving?  If it just keeps sliding on you, sounds like the lock on the axis isn't tightening down enough or the cork pad on the end of it has picked up some grease and needs to be replaced. 



#10 spongebob@55

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Posted 27 August 2014 - 12:52 PM

 

Well here I am, 1 year, 7 months latter and I've been living with it.  But now it seems to be getting worse.    I polar align, then use 3 star allignment, and the GO TO accuracy is great so no problems there.   about a week ago I was out with my f/l 1000mm 4" refractor and then last night I was out with my 180mm f/15 Mak.  Looking through the EP.   The object in the EP moves because of this slop.   The tripod is solid and so is the tripod/mount connection.

So this morning, I put the mount on the table top, lock both axis, extend the counter weight bar shaft, and put my fingers on the end of the counter weight bar shaft, and sure enough, you can get it to move with a slight touch left and right.

Its annoying at the EP.   I wouldn't want a long refractor on this mount with any wind, it would just bounce around.    Even the people who I show the skies to a our public outreach have commented on it.

So what can/should done?

Are there any links or discussion about how to fix this?

I'm about to get a 11" sct for this mount so I'm obsessing about it again.

Thanks for your input.....again.

 

Bob

A little confusion here. Your original post said you were experiencing movement in declination, but in this post quoted here you said you pushed on the counterweight shaft. Pushing on the counterweight shaft effects RA, not dec. so clarification here could be helpful.

 

as for the movement you experience, is it a slight amount of slack you pick up when pushing on the cw shaft, or are you able to push and push and push and it just keeps moving?  If it just keeps sliding on you, sounds like the lock on the axis isn't tightening down enough or the cork pad on the end of it has picked up some grease and needs to be replaced. 

 

Yeah, sorry for my poorly use and lack of proper axis names.    Its the polar axis that has the problem, so when I put the mount on the table, I'm able to slightly and freely nudge the counter weight bar left and right. A very light amount of slack until it stops.   At that point on the end of the counter weight bar about 1-2mm.   The locks are on tightly.  It feels like there's a bit more in the worm and gear interface than there should be.  Or something wrong with the mess???   I have to read the above links more

Thanks

Bob



#11 Lenbo

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Posted 31 August 2014 - 11:03 AM

Hi Bob. I followed the instructions from Astro Baby and adjusted backlash in both axis of my Atlas. I'm pretty careful with balance but it seemed to take a long time calibrating backlash with PHD. There also was a slight amount of movement in both RA and DEC. Typically I usually make things worse before improving them but this seemed to work pretty well. I did very small adjustments and slewed to test for any binding as I went until I heard a very faint tic sound and backed off a tad. Probably not sound procedure but what do I know? I then turned on guiding and watched pretty close. I made one final adjustment to DEC after using for awhile and it seems to be working well. Len
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#12 spongebob@55

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Posted 28 October 2014 - 03:17 PM

Well the problem is getting worse now that I've mounted the heavier 11" Edge to it.   On the last 2 observing nights, what happens is the first alignment fails.  Then the second one is either 'alignment could be poor' / or it says its successful and the go to is very poor, then the 3rd one is usually OK, as long as I do the alignment and slewing with a light 30mm GSO 2" vs a heavy 34mm ES.   Most of the time now i use the up and right as final adjustments.  When I mount the lighter Mak to the mount, its less problematical.   What I think is the slop in the DEC makes the alignment poor when the OTA flips to one side or the other during alignment.   Less so for the lighter scopes.   Also, the noise from the motors seem a little loud. Perhas I have to minimize the backlash, especially on the DEC.

Any ideas?

Thanks

Bob



#13 dotnet

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Posted 29 October 2014 - 02:23 AM

Before you mess with the worm mesh check that the worm axis isn't loose. There are rubber grommets on the mount that you can remove to reveal retaining nuts holding the worm axes in place. If those nuts are loose the worm can move axially and thus introduce play into the afflicted axis. When you adjust those nuts don't tighten them too much, just enough to keep the worm from sliding.

 

Astro Baby's web site has all the pictures and explanations you need to make sense of the above :)

 

Cheers

Steffen.


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#14 orlyandico

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Posted 29 October 2014 - 05:51 AM

Some amount of backlash in both axes is normal. However if it's getting worse either there is end play in the worms or the worm mesh has worked loose.

Probably time to look at the astro baby Web site...
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#15 spongebob@55

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Posted 29 October 2014 - 09:37 AM

Before you mess with the worm mesh check that the worm axis isn't loose. There are rubber grommets on the mount that you can remove to reveal retaining nuts holding the worm axes in place. If those nuts are loose the worm can move axially and thus introduce play into the afflicted axis. When you adjust those nuts don't tighten them too much, just enough to keep the worm from sliding.

 

Astro Baby's web site has all the pictures and explanations you need to make sense of the above :)

 

Cheers

Steffen.

Thanks Steffen,

Is that the 'worm end float adjuster. This is a slotted nut.'?   I don't see any rubber grommets but plastic worm end float covers.   Is that them?

Thanks

Bob



#16 dotnet

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Posted 30 October 2014 - 12:21 AM

Is that the 'worm end float adjuster. This is a slotted nut.'?   I don't see any rubber grommets but plastic worm end float covers.   Is that them?

Thanks

Bob

 

 

Yes, that's it, and yes, that's them. On my HEQ5Pro/Sirius they're hard rubber plugs, I didn't know the NEQ6/Atlas had the upgraded version :)

 

Cheers

Steffen.


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