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CGX play in the RA axis (possible? worked on mine!) solution

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#1 Jim W. S.

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Posted 11 June 2017 - 10:05 AM

Think I found a solution to a problem I have noticed with the CGX mount within the community. The RA having an excessive amount of play and severe tracking issues as well. I finally went ahead and took the mount apart and discovered a problem. The mount has the "spring loaded adjustment" that is within the manual but what they do not document is another adjustment of the actual in/out of the worm block towards the RA gear. (The entire worm block can be adjusted "in and out" towards the RA gear) BTW do not attempt this unless you have some mechanical ability and also fear void of the warranty...

 

Worm_Adjustment.jpg

 

The Green circles show the worm block play as documented within the CGX manual, the red circles hold the worm block in place at a static position in relation the to the RA gear. (The posted image above) Notice that I have removed the motor, if you look where the motor is supposed to be you will see two shafts recessed, these are the hex screws from the bottom image. Blue square.

 

IMG_4099.JPG

 

The third image below shows on the back outside, in between the RA encasement barrel and the motor housing for the RA worm and gear.

 

Worm_Altitude.jpg

 

The red and green circle shows the in/out adjustment of the worm block. (Shown on bottom image)

 

What I did was the loosen all the hex screws within the (top image) both green and red circled. Then on the bottom posted image I adjusted the left and right side  (Both hex screws were very loose) which pushed entire worm block down.

 

*****

Some notes from visual observation while adjusting the hex screws from bottom image. Adjusting the left and right screws you will actually see the entire worm block moving in and out towards the RA gear, I do not know if one side is a lock but what I do see is that as you adjust each hex screw and watch the red circled hex screws from the top image you will see the block move in and out towards the RA gear. A better explanation might be "cant or angle" and these screws adjust the left and right side of the entire block inwards to the RA gear. After getting the worm block to rest on the RA gear, tightening the red circled screws from the top image will set the adjust as permanent.

 

The worm gear settles into the RA gear, which has a concave shape. I found that I can further refine the settings by adjusting the play according to the CGX documentation, then adjusting the entire worm block in and out. The final adjustments have the worm block floating up and down about a 1/32 thru 1/16 of an inch and resting against the RA gear without leaving the sloppy play in the entire RA with the clutch locked.

*****

 

After I had adjusted the entire worm block down where it was riding gently against the RA gear, I tightened the red circled hex screws which hold the worm block in a static position in relation to the RA gear. (Top image) Then adjusted my play according to the CGX manual. I no longer have any of the severe play within the RA axis smile.gif

 

Hope this helps

 

Also would like to give a shout out to glend for his solution on the belt drive as this was what finally made me take the mount apart and inspect the assembly. I am in the process of shimming my motor to get the belt drive adjusted.


Edited by Jim W. S., 11 June 2017 - 01:19 PM.

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#2 DavidCompton

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Posted 21 July 2017 - 10:20 AM

Thank you so much for this post. I don't think many CGX owners will realize but it is gold!

 

I was having an effect the opposite of wobble. I was getting stiction. What would happen is that in my autoguiding, I would see good guiding for a little while (within 1 pixel) then it would jump to 12 pixels and work its way back. The effect was that my stars were horribly bloated in the X axis.

 

I called the nice guy at Hypertune and he said this was not a problem a tune up would fix because he suspected the RA block holding the motor. He said that the block is spring adjusted and it is designed to have the slightest amount of wiggle to make the PE curve smooth instead of sawtooth.  If the RA gear is TOO tight, then the motor has to build up enough torque to break it free. Then it will move a little while until it binds again, then break free. 

 

He said that on all the CGX mounts they have worked on, the RA block is over tightened so that the spring can not act.  He thinks the guys doing the assembly set it correctly in factory for backlash but maybe environmental conditions cause it to lock up. Or maybe they just overtighten so that the axis has zero play to deal with heavy loading of 55 lbs. 

 

That info combined with your post has given me enough intel to find my problem. The CGX manual says the spring load should be movable (but less than 1mm!) and you should be able to move it ever so slightly with your hand. Mine was rock tight. 

 

At first I tried adjusting it 'clockwise' as the manual says. No dice. Then I took the motor off like you did and saw how it works.

 

The larger hex bolt has the spring. The smaller is a stopper (think door stop). If you tighten the stopper all the way down, it will put so much pressure that the spring can't move. Likewise if you tighten down the spring so that it is compressed, you will get no movement. You have to carefully balance the spring tension and the stopper so that you get just enough play to let the spring work, but no so much that is can wobble. If it is locked down, you have to loosen it 'counterclockwise'!

 

Also, the other set of two screws in your picture has a job. It raises and lowers the block to mesh the RA gear to the worm. If it is cranked down, the spring has no play either. You have to lossen it just enough to let the spring function, but not too much. 

 

I think that many of the issues are temperature related. I am in a hot climate right now and I think the metal has expanded so that it froze up. It only takes a miniscule adjustment to get it moving. I think that in the winter I will have to check my guiding. It could start wobbling if the cold shrinks things up.

 

If any of you guys have a wobble or contrary if your guiding has bad stiction, then this is how you can adjust it.


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#3 MartyBolton

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Posted 21 July 2017 - 12:41 PM

thanks!  I have to look at mine! I am still waiting for better seeing to determine if its guiding related or the same problems you guys have.  My first impressions were I have some issue because I can't seem to get it to hold the .75 - 1" bullseye where with my CGEM DX that was easy and consistent.  Can you post an image of your guiding with and/or without the issue?

thanks

Marty



#4 DavidCompton

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Posted 23 July 2017 - 03:57 PM

I've posted 4 U-Tube videos on this subject, attempted to clear up some questions…..

I think you might enjoy viewing all four…   #3 was a “wrap up” explaining what was going on…  #4 is the actual “test” at night.

https://www.youtube....h?v=WnfxFa9C1fE   First U-tube – Explains problem, and 1st attempt adjusting

https://www.youtube....h?v=sn-LnxdVxYs   Part 2 – Goes into  “screws # 3; 4; 5; and 6” area

https://www.youtube....h?v=x2fT8IwzKAI    Part 3 – “Wrap Up” Discussion

 

https://www.youtube....h?v=yV62euc2xe8  Part 4 – Tracking problem fix tested at night with autoguiding

 

And for fun, I attached the photo taken with the test run. I only did basic calibration and a mild deconvolution.

 

If you take a look and the videos help, please 'like' them so they will so up in U-tube searches for other people.

 

M52 LRGB

Edited by DavidCompton, 23 July 2017 - 10:59 PM.

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#5 DavidCompton

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Posted 23 July 2017 - 04:02 PM

thanks!  I have to look at mine! I am still waiting for better seeing to determine if its guiding related or the same problems you guys have.  My first impressions were I have some issue because I can't seem to get it to hold the .75 - 1" bullseye where with my CGEM DX that was easy and consistent.  Can you post an image of your guiding with and/or without the issue?

thanks

Marty

Marty, I don't know if the DX has spring loaded blocks that hold the drive gears. The issue I specifically was working on was related to the spring loading and the tension on the screws. It is mentioned in the 'backlash' adjustment on the last pages of the CGX manual. You can look at the pictures in the manual and see if the setup is similar.



#6 Jim W. S.

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Posted 24 July 2017 - 07:16 PM

Thank you so much for this post. I don't think many CGX owners will realize but it is gold!

 

I was having an effect the opposite of wobble. I was getting stiction. What would happen is that in my autoguiding, I would see good guiding for a little while (within 1 pixel) then it would jump to 12 pixels and work its way back. The effect was that my stars were horribly bloated in the X axis.

 

I called the nice guy at Hypertune and he said this was not a problem a tune up would fix because he suspected the RA block holding the motor. He said that the block is spring adjusted and it is designed to have the slightest amount of wiggle to make the PE curve smooth instead of sawtooth.  If the RA gear is TOO tight, then the motor has to build up enough torque to break it free. Then it will move a little while until it binds again, then break free. 

 

He said that on all the CGX mounts they have worked on, the RA block is over tightened so that the spring can not act.  He thinks the guys doing the assembly set it correctly in factory for backlash but maybe environmental conditions cause it to lock up. Or maybe they just overtighten so that the axis has zero play to deal with heavy loading of 55 lbs. 

 

That info combined with your post has given me enough intel to find my problem. The CGX manual says the spring load should be movable (but less than 1mm!) and you should be able to move it ever so slightly with your hand. Mine was rock tight. 

 

At first I tried adjusting it 'clockwise' as the manual says. No dice. Then I took the motor off like you did and saw how it works.

 

The larger hex bolt has the spring. The smaller is a stopper (think door stop). If you tighten the stopper all the way down, it will put so much pressure that the spring can't move. Likewise if you tighten down the spring so that it is compressed, you will get no movement. You have to carefully balance the spring tension and the stopper so that you get just enough play to let the spring work, but no so much that is can wobble. If it is locked down, you have to loosen it 'counterclockwise'!

 

Also, the other set of two screws in your picture has a job. It raises and lowers the block to mesh the RA gear to the worm. If it is cranked down, the spring has no play either. You have to lossen it just enough to let the spring function, but not too much. 

 

I think that many of the issues are temperature related. I am in a hot climate right now and I think the metal has expanded so that it froze up. It only takes a miniscule adjustment to get it moving. I think that in the winter I will have to check my guiding. It could start wobbling if the cold shrinks things up.

 

If any of you guys have a wobble or contrary if your guiding has bad stiction, then this is how you can adjust it.

Your welcome. I had a lot of motivation 'glend' has definitely helped me with his detailed explanations and his threads on the CGX. I felt compelled to really look at this problem as it seems to be a common complaint within the CGX threads.

 

I viewed your Youtube videos and they are great, I sent you a message that if you wanted to use the above photos on your 'chalkboard' #3 video to help demonstrate please do :)


Edited by Jim W. S., 24 July 2017 - 07:17 PM.


#7 Jim W. S.

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Posted 24 July 2017 - 07:29 PM

thanks!  I have to look at mine! I am still waiting for better seeing to determine if its guiding related or the same problems you guys have.  My first impressions were I have some issue because I can't seem to get it to hold the .75 - 1" bullseye where with my CGEM DX that was easy and consistent.  Can you post an image of your guiding with and/or without the issue?

thanks

Marty

I am assuming that you are comparing your DX to the CGX? If this is so (I don't want to assume) it very well may be that this might help. Dave Compton was having stricture, I was having severe play. (A free play left and right on the RA axis) the above fix moves the entire worm block (motor, worm block, worm drive and assembly) in/up and out/down towards the RA axis gear, then uses the Celestron manual to adjust the floating play. (call this a yaw or pitch) Dave Comptons video shows in a visual were mine is text accompanied by photos... Between the two you should be able to tell what is occurring with your mount, hopefully.

 

Yeah it is kinda daunting taking apart the mount in such a fashion but it really gives a better glimpse on what is happening inside and the undocumented adjustment I try to explain above. 


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#8 driven

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Posted 25 July 2017 - 01:33 PM

I have a one week old CGX-L with the deluxe package: binding AND screeching noise on both RA and Dec.  Binding is easy to fix but the noise takes more finesse and patience. I've read every post on this subject three times and watched DavidComptons's videos (thanks David!) but I haven't seen a concise description of just what the two main adjustment screws do, so  here's my take on it.

 

For reference, imagine that the worm wheel is vertical and the worm block/motor are on top of it.  The worm block pivots, and the pivot point is behind the axis of the worm gear.  So when the worm block pivots the worm gear moves up and down (farther from or closer to the worm wheel, respectively) while the motor moves back and forth horizontally.  They actually move in arcs, but over this short range of motion we'll just use the simple terms to describe the motion.  Push the motor back and the worm gear will lift off the wheel.  Release it and the spring will push the worm gear back onto the wheel.

 

The limit and distance screws are in a push-pull configuration.  They can be used to lock the worm block in one place but that is not their intent.  What they do is limit the range of motion of the block.  The distance screw is the pull screw - it has a head and passes through the block, threading into a plate behind it.  Tighten this screw and it will pull the block back and lift the worm gear off the wheel.  It is used to set the limit for how close the worm can get to the wheel.  If you have noise, the worm is too close and has too much pressure on the wheel.  Tighten the distance screw in little bits (1/16 of a turn) until the noise stops.  And as you have noticed if you are working with these screws, it takes a 3mm wrench, not a 2.5mm like the manual says.

 

The limit screw is the push screw.  It has no head and is threaded into the block and can push against the back plate.  It is used to limit the amount of block pivot, or how far the worm can get away from the wheel.  This is the one that should be set to allow for 1mm of worm travel.  If you have binding you probably have less than 1mm of worm travel, or even none, as mine was from the factory.  Just loosen this screw until there is 1mm of travel.  I would just loosen it a lot until the distance screw is properly set, and then only at the end adjust the limit screw to limit travel to 1mm.

 

So, binding is easy to fix.  Loosen the limit screw.  Done.  The thing with the noise, at least in my case, is that it is inconsistent.  Sometimes it happens and sometimes it doesn't.  What is consistent is that when it does happen, it happens at the same place around the worm wheel every time.  In the Utility menu do Get Axis Position and you will see the angular positions of each axis.  My noise would only happen on each axis when slewing counterclockwise.  All clockwise motion is silent.  My procedure was to find a noisy spot on the wheel and tighten the distance screw until the noise stopped, then slewing back and forth over the spot to ensure it was gone.  Then slewing all the way in both directions multiple times.  Then cursing the plastic covers while reinstalling them.  Then dropping a screw and cursing more.

 

I can't yet say what the backlash looks like.  No actual astronomy has been done yet, but hopefully after my third run of silencing the noise it will stay quiet and allow me to put a camera on soon.


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#9 DavidCompton

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Posted 25 July 2017 - 02:49 PM

driven,

 

Yes. I had a horrible noise problem as well. I just started a post about the CGX mount and I will be posting all the videos I've made from the start. I have gone through 2 mounts and I'm on #3.

 

The first mount the DEC axis wouldn't respond at all.

 

The second mount was making a horrible noise in RA when slewing in one direction as well. I likened it to a seal, like the animal, like 'Ahr Ahr Ahr'. No joke. I sent the video to Celestron to diagnose it and they said to send it back. Their default response.

 

I'm trying to get the videos edited and roll them out every couple of days as I have time.

 

I want to love this mount. But man is it trying on the patience. I'm not a Celestron fanboy, but I do like this mount's features.



#10 DavidCompton

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Posted 25 July 2017 - 02:52 PM

I have a one week old CGX-L with the deluxe package: binding AND screeching noise on both RA and Dec.  Binding is easy to fix but the noise takes more finesse and patience. I've read every post on this subject three times and watched DavidComptons's videos (thanks David!) but I haven't seen a concise description of just what the two main adjustment screws do, so  here's my take on it.

 

Yep, I think you have described it very well. One of the screws seems to be a 'stopper' designed to limit the inward travel. The fact that the other is screwed to the block limits the outward travel. You want just enough play so the gear rides smoothly on the worm. But it seems finicky.



#11 glend

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Posted 25 July 2017 - 05:50 PM

There is no inward stopper per se. The worm gear adjustment screw identifiers and technique for adjustment are published on page 25 of the CGX manual. There a is a target range for the worm spring loading pull back. I believe most of these mounts are shipping from the factory binding, mine certainly was. The claims that all the original factory setup issues have been resolved, is clearly not the case as we continually see these popping up here.  Celestron (USA) does not inspect or tune any of these mounts, they are shipped from Synta (China) direct to distributors or major retailers. Boxes are unopened until you open them. Poor out of the box performance is entirely a factory setup and  QA issue. Frankly i doubt any testing is done on worm setup and what you get depends on who assembled it on the day. That means anyone buying a CGX or CGX/L needs to educate themselves on how to set this mount drive up properly.  Sadly, its like buying a car and finding out you need to setup the fuel injection timing yourself. Only astronomers will put up with this sort of QA.


Edited by glend, 25 July 2017 - 05:53 PM.

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#12 Jim W. S.

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Posted 25 July 2017 - 06:20 PM

I have a one week old CGX-L with the deluxe package: binding AND screeching noise on both RA and Dec.  Binding is easy to fix but the noise takes more finesse and patience. I've read every post on this subject three times and watched DavidComptons's videos (thanks David!) but I haven't seen a concise description of just what the two main adjustment screws do, so  here's my take on it.

 

For reference, imagine that the worm wheel is vertical and the worm block/motor are on top of it.  The worm block pivots, and the pivot point is behind the axis of the worm gear.  So when the worm block pivots the worm gear moves up and down (farther from or closer to the worm wheel, respectively) while the motor moves back and forth horizontally.  They actually move in arcs, but over this short range of motion we'll just use the simple terms to describe the motion.  Push the motor back and the worm gear will lift off the wheel.  Release it and the spring will push the worm gear back onto the wheel.

 

The limit and distance screws are in a push-pull configuration.  They can be used to lock the worm block in one place but that is not their intent.  What they do is limit the range of motion of the block.  The distance screw is the pull screw - it has a head and passes through the block, threading into a plate behind it.  Tighten this screw and it will pull the block back and lift the worm gear off the wheel.  It is used to set the limit for how close the worm can get to the wheel.  If you have noise, the worm is too close and has too much pressure on the wheel.  Tighten the distance screw in little bits (1/16 of a turn) until the noise stops.  And as you have noticed if you are working with these screws, it takes a 3mm wrench, not a 2.5mm like the manual says.

 

The limit screw is the push screw.  It has no head and is threaded into the block and can push against the back plate.  It is used to limit the amount of block pivot, or how far the worm can get away from the wheel.  This is the one that should be set to allow for 1mm of worm travel.  If you have binding you probably have less than 1mm of worm travel, or even none, as mine was from the factory.  Just loosen this screw until there is 1mm of travel.  I would just loosen it a lot until the distance screw is properly set, and then only at the end adjust the limit screw to limit travel to 1mm.

 

So, binding is easy to fix.  Loosen the limit screw.  Done.  The thing with the noise, at least in my case, is that it is inconsistent.  Sometimes it happens and sometimes it doesn't.  What is consistent is that when it does happen, it happens at the same place around the worm wheel every time.  In the Utility menu do Get Axis Position and you will see the angular positions of each axis.  My noise would only happen on each axis when slewing counterclockwise.  All clockwise motion is silent.  My procedure was to find a noisy spot on the wheel and tighten the distance screw until the noise stopped, then slewing back and forth over the spot to ensure it was gone.  Then slewing all the way in both directions multiple times.  Then cursing the plastic covers while reinstalling them.  Then dropping a screw and cursing more.

 

I can't yet say what the backlash looks like.  No actual astronomy has been done yet, but hopefully after my third run of silencing the noise it will stay quiet and allow me to put a camera on soon.

The inclusion of the images are meant to be helpful. Yes I feel that my wording is limited but I attempted to show an adjustment that is not documented. The entire assembly: motor, worm gear, block holding the worm gear can be moved in towards the RA axis gear or away from the RA axis gear. This is what I am showing in the images and between the two adjustments you can get the mount to relieve stricture and the dreaded 'death wobble'. My mount had a severe issue of RA wobble, I could literally move my mount on the RA about 3-4mm in total.

 

What I found is that by moving the entire block into the RA axis gear then doing the documented adjustment I resolved the issue. I found that by loosening the two circled red hex heads, (top image) then using the red and green circled hex heads will move the entire assembly (motor, worm gear, block holding the worm gear) inward or outward towards the RA axis gear. You have to physically manipulate the entire block in the direction you want it to travel. Tightening the hex head screws (both circled red) will place the entire assembly in a static position. Then using the documentation from Celestron will give you the finer detail of the 'floating' worm. Really when you take the mount apart like I did then it becomes apparent that the second adjustment is a factory or bench adjustment... Most likely not done or even thought of within QA at the factory.

 

I agree with Glen on this subject as I have had to do several modifications on the mount to get performance that should be much better out of the box...


Edited by Jim W. S., 25 July 2017 - 06:36 PM.


#13 driven

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Posted 25 July 2017 - 10:25 PM

The second mount was making a horrible noise in RA when slewing in one direction as well. I likened it to a seal, like the animal, like 'Ahr Ahr Ahr'. No joke.

That is the best description of the noise that I've seen yet!

 

 

Thank you so much for this post. I don't think many CGX owners will realize but it is gold!

This is so true.  This thread has by far the most information about all the adjustments that are possible with the worm block assembly.  Discussion of the worm noise is perhaps not directly on topic, but this seemed to be the best thread to further describe what adjustments can be made and what they do.  RA play, seal noises, binding, and backlash are all issues that can be best solved when the causes and methods of remedy are fully understood.

 

 

The inclusion of the images are meant to be helpful. Yes I feel that my wording is limited but I attempted to show an adjustment that is not documented.

You have succeeded, and for this we thank you!

 


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#14 Jim W. S.

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Posted 26 July 2017 - 07:38 PM

There is no inward stopper per se. The worm gear adjustment screw identifiers and technique for adjustment are published on page 25 of the CGX manual. There a is a target range for the worm spring loading pull back. I believe most of these mounts are shipping from the factory binding, mine certainly was. The claims that all the original factory setup issues have been resolved, is clearly not the case as we continually see these popping up here.  Celestron (USA) does not inspect or tune any of these mounts, they are shipped from Synta (China) direct to distributors or major retailers. Boxes are unopened until you open them. Poor out of the box performance is entirely a factory setup and  QA issue. Frankly i doubt any testing is done on worm setup and what you get depends on who assembled it on the day. That means anyone buying a CGX or CGX/L needs to educate themselves on how to set this mount drive up properly.  Sadly, its like buying a car and finding out you need to setup the fuel injection timing yourself. Only astronomers will put up with this sort of QA.

 

I agree with you on this subject as I have had to do several modifications on the mount to get performance that should be much better out of the box...



#15 MartyBolton

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Posted 28 July 2017 - 08:14 PM

HI guys, sorry I've been away - it has been horrible seeing in CT, looking forward to tomorrow night maybe.  Question - when you guys are adjusting these things, are you taking your whole imaging rig down?  And in daylight?  I have my mount on a pier and I'm wondering do I adjust these all under load or no load?  I don't think mine was as bad off as yours but I will indeed make sure I can tune this, cause I'm not happy with what I had last few weeks.  I have been able to go up to 3 min, if you want to see recent work of say dumbell - check out astrobin\martybolton.  I also had custom mounting blocks made by Dave Yates? search for that here and you can order some blocks from him.

 

thanks for all the replies, I will have to come back this weekend and make some adjustments.



#16 Jim W. S.

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Posted 28 July 2017 - 09:05 PM

HI guys, sorry I've been away - it has been horrible seeing in CT, looking forward to tomorrow night maybe.  Question - when you guys are adjusting these things, are you taking your whole imaging rig down?  And in daylight?  I have my mount on a pier and I'm wondering do I adjust these all under load or no load?  I don't think mine was as bad off as yours but I will indeed make sure I can tune this, cause I'm not happy with what I had last few weeks.  I have been able to go up to 3 min, if you want to see recent work of say dumbell - check out astrobin\martybolton.  I also had custom mounting blocks made by Dave Yates? search for that here and you can order some blocks from him.

 

thanks for all the replies, I will have to come back this weekend and make some adjustments.

I would suggest without load. The adjustments can be done without removing the motor or belt.


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#17 JoeR

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Posted 29 July 2017 - 10:10 AM

Thanks for these videos I've been having issues like these mentioned and they certainly helped. I even put a little pluck foam in the gear boxes to try to dampen the loud noises. So this time I went into the gear boxes took out my foam and tightened down both Dec & RA distance adjustment screws on the motors until there was no movement. Then VERY gradually loosened them until there was just a little movement only 1mm play. There was a little too much before in my RA and way too much in my Dec. Last night I had a long imaging session and it went flawlessly! 180 subs and not one reject. There was a still a little vibration noise at one point when I was slewing a little in the zenith, but not nearly as bad as before and only that one time. When I was doing my 2+4 alignment & calibration it was totally quiet, and this is with a C14 & three 22lb counterweights. Balance is also a key I had that east bias sweet spot figured out the RA and the rear heavy bias in the Dec. The CGX/L manual doesn't really help with balancing for imaging but there's a good explanation on pg 23 in the Astro-Physics Mach1 manual. I followed that and everything was smooth. The Losmandy G11 users have the advantage of a large user network of online support so lets keep it coming on these CGX/L user tips!

 

This a from a single unprocessd FIT from the evening with one quick level boost cropped & zoomed in. NGC 7380 120 seconds unguided C14 Hyperstar H-Alpha ASI1600MM. All my subs had tight stars like this.

 

NGC7380raw.jpg


Edited by JoeR, 29 July 2017 - 05:56 PM.

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#18 mac4lyfe

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Posted 30 July 2017 - 12:15 PM

I'm really wanting to buy a CGX/L but these issues are causing me to pause? I love the price to payload but wondering if I need to spend more on something with less issues?



#19 driven

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Posted 30 July 2017 - 10:39 PM

During my first unsuccessful attempts at getting rid of the worm noise I was thinking "why didn't I just spend more on something with less issues".  Then I figured out just what the heck the adjustments did and was able to solve the noise and binding issues.  I'm a tinkerer and have taken apart almost everything I've ever owned, and now I'm glad I saved a few thousand dollars.  The CGX-L seems to be the current sweet spot for features and capabilities for the price.  The cost is you might have to do some of your own fine tuning.  If you order one I suggest doing so from someplace that is out of stock with the hope that you will get one of the "fresher" ones from the factory and hopefully better adjusted.  If you want something that just works and are not comfortable doing your own tuning you should spend more.  You'll still have problems, but they will be different problems and probably won't involve opening up the mount.


Edited by driven, 30 July 2017 - 11:26 PM.

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#20 MartyBolton

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Posted 04 August 2017 - 02:53 PM

Hi guys, I finally got around to create a video to share here - maybe you can give me some ideas of what you think I have after tweaking the RA and DEC adjustment settings as described here.  Thank you to everyone for this great thread!  And Dave Compton for all your videos.  After shooting this, I realized I got way better results in DEC after just not guiding at all or going one direction.  As for RA - I'm hoping you guys can comment on the video.  Let me know what you think I should try next.  I have to eliminate seeing as an issue before I try anything next.  But I'm curious - how can we dial this RA in the bulls-eye without it being flat and wobbling all over the place.  I think I need to do way better than this for 5m exposures.... 

thanks

 

ref:

https://youtu.be/u2tJ1JKCz-s


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#21 UlteriorModem

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Posted 19 September 2017 - 03:36 PM

I made some adjustments to the mount following the info in this thread.

 

First night out it worked fine but there was not a huge improvement.

 

Last night however I hit the classic 'stiction' problem.

 

36494337784_936469ddef_c.jpgStiction by Tom Whit, on Flickr

 

I guess it only happens in certain orientation of the mount.

 

Moral of the story check for binding / stiction for the full movement of the moun!



#22 ZL4PLM

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Posted 19 September 2017 - 06:38 PM

I'm really wanting to buy a CGX/L but these issues are causing me to pause? I love the price to payload but wondering if I need to spend more on something with less issues?

ditto ... I want a new mount for my obs pier but as much as I want to love the CGX as much as I do my CGEM I am afraid its off the list - I am in NZ and can't afford to spend $ shipping backwards and forwards across the globe to fix issues like this.

 

Sorry Celestron lost me as a customer :(



#23 DavidCompton

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Posted 28 September 2017 - 02:33 PM

JoeR, The picture you posted is great, and I think it shows the capability of the mount. I think as we have all been experiencing issues and public shaming them, I hope Celestron pays attention and fixes it for future users. 



#24 driven

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Posted 03 November 2017 - 01:37 AM

So now that the weather has cooled off some, I started to get some of the seal barking noise in the RA axis again on slew speeds 7-9.  When I took off the plastic covers I noticed that there was an uneven distribution of grease on the worm.  So instead of adjusting the screws, I added more grease and this made the noise go away almost entirely.  I also noticed that the grease is almost black.  Honestly I don't remember what color it started out as, so I don't know if this means anything.  I foresee a worm wheel regreasing somewhere in my not too distant future.  This could have been the problem all along!



#25 glend

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Posted 03 November 2017 - 02:20 AM

So now that the weather has cooled off some, I started to get some of the seal barking noise in the RA axis again on slew speeds 7-9.  When I took off the plastic covers I noticed that there was an uneven distribution of grease on the worm.  So instead of adjusting the screws, I added more grease and this made the noise go away almost entirely.  I also noticed that the grease is almost black.  Honestly I don't remember what color it started out as, so I don't know if this means anything.  I foresee a worm wheel regreasing somewhere in my not too distant future.  This could have been the problem all along!

Black grease is not normal unless rhe factory has changed lubricants. My grease is very translucent tan in color.




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