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Eq6 r pro Guiding spikes and egg shaped stars

Sky-Watcher EQ6 Pro Equatorial Mount Guiding Troubleshooting
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SolarVortex3562 avatar
SolarVortex3562 avatar
Hi, my Eq6 r pro guides at about .4 to .3 rms for about 5 minutes then it has a real quick guiding spike of about 2" to 4" and it causes either egg shaped stars or double stars. The mount then goes back to .4 to .3 rms again. I don't know what causes them but they are a real inconvenience. I will try to take a photo of my guide graph when I get the chance and provide a picture as well. But until then I want to know what you guys think the issue is and maybe how to fix it. 
Setup used:
Askar 120 apo 1x flattener
2600mm pro
250mm guidescope 
120mm guidecamera
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V avatar
V avatar
Hi, my Eq6 r pro guides at about .4 to .3 rms for about 5 minutes then it has a real quick guiding spike of about 2" to 4" and it causes either egg shaped stars or double stars.  I don't know what causes them but they are a real inconvenience. I will try to take a photo of my guide graph when I get the chance and provide a picture as well. But until then I want to know what you guys think the issue is and maybe how to fix it. 
Setup used:
Askar 120 apo 1x flattener
2600mm pro
250mm guidescope 
120mm guidecamera

Loosen or Tighten your DEC backlash a littlebit, the DEC on the 6R can slop to 1 or 2" and sustain that for minutes on end, and in bad cases, 3-5".
NeilM avatar
NeilM avatar
Sounds like maybe it could be backlash?  Have you seen the lazy geek’s YouTube video on adjusting EQ6 backlash?  He also shows a primitive way of checking if you have backlash in the first place.  Of course it could be a different issue but this came to mind.
SolarVortex3562 avatar
SolarVortex3562 avatar
Hi, my Eq6 r pro guides at about .4 to .3 rms for about 5 minutes then it has a real quick guiding spike of about 2" to 4" and it causes either egg shaped stars or double stars.  I don't know what causes them but they are a real inconvenience. I will try to take a photo of my guide graph when I get the chance and provide a picture as well. But until then I want to know what you guys think the issue is and maybe how to fix it. 
Setup used:
Askar 120 apo 1x flattener
2600mm pro
250mm guidescope 
120mm guidecamera

Loosen or Tighten your DEC backlash a littlebit, the DEC on the 6R can slop to 1 or 2" and sustain that for minutes on end, and in bad cases, 3-5".

 
Hi, my Eq6 r pro guides at about .4 to .3 rms for about 5 minutes then it has a real quick guiding spike of about 2" to 4" and it causes either egg shaped stars or double stars.  I don't know what causes them but they are a real inconvenience. I will try to take a photo of my guide graph when I get the chance and provide a picture as well. But until then I want to know what you guys think the issue is and maybe how to fix it. 
Setup used:
Askar 120 apo 1x flattener
2600mm pro
250mm guidescope 
120mm guidecamera

Loosen or Tighten your DEC backlash a littlebit, the DEC on the 6R can slop to 1 or 2" and sustain that for minutes on end, and in bad cases, 3-5".

I have already adjusted my backlash for RA. It feels like there is very little to no backlash in the mount.
Well Written
V avatar
V avatar
Hi, my Eq6 r pro guides at about .4 to .3 rms for about 5 minutes then it has a real quick guiding spike of about 2" to 4" and it causes either egg shaped stars or double stars.  I don't know what causes them but they are a real inconvenience. I will try to take a photo of my guide graph when I get the chance and provide a picture as well. But until then I want to know what you guys think the issue is and maybe how to fix it. 
Setup used:
Askar 120 apo 1x flattener
2600mm pro
250mm guidescope 
120mm guidecamera

Loosen or Tighten your DEC backlash a littlebit, the DEC on the 6R can slop to 1 or 2" and sustain that for minutes on end, and in bad cases, 3-5".

I have already adjusted my backlash for DEC and RA. It feels like there is very little to no backlash in the mount.

It truely depends on the season and temperature of the mount, I've noted it gets looser in the cold, and tighter during the summer.
SolarVortex3562 avatar
SolarVortex3562 avatar
I did adjust the backlash a month ago(It's been cloudy so I haven't had the chance to test until now) is it possible to get a result like this my putting the gears to tight together?.
V avatar
V avatar
I did adjust the backlash a month ago(It's been cloudy so I haven't had the chance to test until now) is it possible to get a result like this my putting the gears to tight together?.

That is a possibility. Remember to loosen the 4 housing screws when you do it for optimal meshing.
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Björn Arnold avatar
Björn Arnold avatar
@SolarVortex3562 please slow down and don‘t rush to actions. You should properly analyse the situation and take informed actions.
First, please check the direction of the elongation of the stars. If the elongation is along the RA axis you may have issues with the RA worm and Dec is likely not the issue.
If you are using phd2 for guiding, you may try using the cross-test in which phd2 draws a cross during a longer exposure which may help to see if the axes‘ response is significantly unbalanced. 

The information you‘re providing does not warrant any mechanical changes. In the worst case, you may throw a good Dec backlash setup off.
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David Russell avatar
David Russell avatar
run guiding assistant in PHD2, as this measures your backlash and identifies if its excessive.

uploading a PHD2 log file would be very useful if you want to get people to take a look at the mount corrections and behaviour.
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SolarVortex3562 avatar
SolarVortex3562 avatar
Björn Arnold:
@SolarVortex3562 please slow down and don‘t rush to actions. You should properly analyse the situation and take informed actions.
First, please check the direction of the elongation of the stars. If the elongation is along the RA axis you may have issues with the RA worm and Dec is likely not the issue.
If you are using phd2 for guiding, you may try using the cross-test in which phd2 draws a cross during a longer exposure which may help to see if the axes‘ response is significantly unbalanced. 

The information you‘re providing does not warrant any mechanical changes. In the worst case, you may throw a good Dec backlash setup off.

After checking the Elongation is in the RA axis.  Last month I only adjusted backlash in Ra and did nothing in Dec. Also I use the asi air for guiding so I would need a laptop for phd2.
Björn Arnold avatar
Björn Arnold avatar
Björn Arnold:
@SolarVortex3562 please slow down and don‘t rush to actions. You should properly analyse the situation and take informed actions.
First, please check the direction of the elongation of the stars. If the elongation is along the RA axis you may have issues with the RA worm and Dec is likely not the issue.
If you are using phd2 for guiding, you may try using the cross-test in which phd2 draws a cross during a longer exposure which may help to see if the axes‘ response is significantly unbalanced. 

The information you‘re providing does not warrant any mechanical changes. In the worst case, you may throw a good Dec backlash setup off.

After checking the Elongation is in the RA axis.  Last month I only adjusted backlash in Ra and did nothing in Dec. Also I use the asi air for guiding so I would need a laptop for phd2.

If it's in the RA axis, there may be several things one should check. First of all, RA backlash is usually less of an issue in guiding as one does not reverse the rotation of the worm drive unless guiding rates are very close or even larger than sidereal rate, which would be questionable on its own. What can make RA backlash being observable is an excellent balance and wind or any other force acting on the axis. Therefore, one usually uses a slight imbalance on the RA to assure that the gear is always in interaction.

Another issue is something that another AP colleague is currently facing which can be some issue/damage in the worm gear. In his case, the star basically jumps from one position to another and returns after a few seconds. He suspects that a collision with the axis might have had an impact on the worm gear. I'm not saying that his might be the case for you but can be seen as very sudden changes in the RA rate. Therefore, I agree with the previous post to run phd2 guiding assistant which will observe the tracking behavior and which also indicates sudden RA movement.
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Romain Dechamps avatar
Romain Dechamps avatar
Do you have an dew heater on your guide scope? If so, did you tried to shut it off? I did this with mine, went from 1.0 / 0.8 RMS with a lot of bumps to a steady 0.4 with my EQ6R.
Concise
Monty Chandler avatar
Monty Chandler avatar
What did you learn from the PHD2 guide assistant after calibrating?
Tom Marsala avatar
Tom Marsala avatar
1 minor thing you could also check are the belts. They could be too loose or there might be something caught in one of the teeth or the cogs causing a spike. Worth a check
Concise
SolarVortex3562 avatar
SolarVortex3562 avatar
Do you have an dew heater on your guide scope? If so, did you tried to shut it off? I did this with mine, went from 1.0 / 0.8 RMS with a lot of bumps to a steady 0.4 with my EQ6R.

I don't get it. How does turning off a dew heater help your guiding?
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Romain Dechamps avatar
Romain Dechamps avatar
Do you have an dew heater on your guide scope? If so, did you tried to shut it off? I did this with mine, went from 1.0 / 0.8 RMS with a lot of bumps to a steady 0.4 with my EQ6R.

I don't get it. How does turning off a dew heater help your guiding?

*** I believe it makes my stars blurried, maybe it due to voltage or something else. Truth is, I tried twice when turning it off the RMS lowered***
Mark Fox avatar
Mark Fox avatar
Hi, my Eq6 r pro guides at about .4 to .3 rms for about 5 minutes then it has a real quick guiding spike of about 2" to 4" and it causes either egg shaped stars or double stars. The mount then goes back to .4 to .3 rms again. I don't know what causes them but they are a real inconvenience. I will try to take a photo of my guide graph when I get the chance and provide a picture as well. But until then I want to know what you guys think the issue is and maybe how to fix it. 
Setup used:
Askar 120 apo 1x flattener
2600mm pro
250mm guidescope 
120mm guidecamera

Yes, it would be good to see the guiding graphs. I run an SCT on the EQ6RPro and have similar issues with bumps in guiding, although they are somewhat more random and farther apart.  Also, how much counterweight are you using, and are you extending the counterweight rod to its fullest extent?  I found on my mount, the CW bar had some wiggle to it due to a poorly matched delrin washer on the internal portion of the rod.  You may want to make sure that you don't fully extend the CW rod to reduce the magnitude of bar wobble (but of course still balance the setup) --- if it is at all an issue in your situation.  Just bringing it up for consideration.
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SolarVortex3562 avatar
SolarVortex3562 avatar
The guiding is like this most of the time
The spikes in guiding that occur. The guiding going from good to bad.
I need to grab a timer to see if the spikes are periodic or random.
Despite the spikes appearing in both DEC and RA I'm only getting elongated stars in RA
SolarVortex3562 avatar
SolarVortex3562 avatar
Mark Fox:
Hi, my Eq6 r pro guides at about .4 to .3 rms for about 5 minutes then it has a real quick guiding spike of about 2" to 4" and it causes either egg shaped stars or double stars. The mount then goes back to .4 to .3 rms again. I don't know what causes them but they are a real inconvenience. I will try to take a photo of my guide graph when I get the chance and provide a picture as well. But until then I want to know what you guys think the issue is and maybe how to fix it. 
Setup used:
Askar 120 apo 1x flattener
2600mm pro
250mm guidescope 
120mm guidecamera

Yes, it would be good to see the guiding graphs. I run an SCT on the EQ6RPro and have similar issues with bumps in guiding, although they are somewhat more random and farther apart.  Also, how much counterweight are you using, and are you extending the counterweight rod to its fullest extent?  I found on my mount, the CW bar had some wiggle to it due to a poorly matched delrin washer on the internal portion of the rod.  You may want to make sure that you don't fully extend the CW rod to reduce the magnitude of bar wobble (but of course still balance the setup) --- if it is at all an issue in your situation.  Just bringing it up for consideration.

I'm using 18.5 pounds worth of counterweights (11pounds and 7.5 pounds). My CW bar also has some wiggle in it but is not extended to it fullest extent.
Mark Fox avatar
Mark Fox avatar
Mark Fox:
Hi, my Eq6 r pro guides at about .4 to .3 rms for about 5 minutes then it has a real quick guiding spike of about 2" to 4" and it causes either egg shaped stars or double stars. The mount then goes back to .4 to .3 rms again. I don't know what causes them but they are a real inconvenience. I will try to take a photo of my guide graph when I get the chance and provide a picture as well. But until then I want to know what you guys think the issue is and maybe how to fix it. 
Setup used:
Askar 120 apo 1x flattener
2600mm pro
250mm guidescope 
120mm guidecamera

Yes, it would be good to see the guiding graphs. I run an SCT on the EQ6RPro and have similar issues with bumps in guiding, although they are somewhat more random and farther apart.  Also, how much counterweight are you using, and are you extending the counterweight rod to its fullest extent?  I found on my mount, the CW bar had some wiggle to it due to a poorly matched delrin washer on the internal portion of the rod.  You may want to make sure that you don't fully extend the CW rod to reduce the magnitude of bar wobble (but of course still balance the setup) --- if it is at all an issue in your situation.  Just bringing it up for consideration.

I'm using 18.5 pounds worth of counterweights (11pounds and 7.5 pounds). My CW bar also has some wiggle in it but is not extended to it fullest extent.

@SolarVortex3562 , thanks.  I'm using 2 x 11pounds, and until recently have been using the CW bar at full extent.  Unfortunately, I have not retested the mount after installing a larger hand-made spacer, nor tried the setup with partial CW extension. It sounds as if your issue is probably not related to this CW bar slop if it is happening on the order of every 5 minutes.  I hope you can get some good answers and solve the issue.
Mark
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SolarVortex3562 avatar
SolarVortex3562 avatar
Update, I tuned the backlash on RA so that I had a tiny tiny bit of play in the gears and that seemed to remove my large guiding spikes in Ra. I still have spikes but they are now near 1" instead of 2-4." I also want to mention that early in the night for about the first 2 hours I had no guiding spikes at all and then over time they started to become more common.
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NeilM avatar
NeilM avatar
You are welcome
Tom Marsala avatar
Tom Marsala avatar
Interesting that a de-tune in the RA helped! Good to know. Makes me wonder now if I should go back and do the same. 
Tom
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