Atik 16200 vibrations?

[Big Bang!]

I wonder if there is anybody on here who has experience with the Atik 16200 who might be able to help me. 

I have just upgraded from an Atik One 9.0 to an Atik 16200 to give me a Large Format capability.  The Atik One has been superb with no issues of any kind; a real pleasure to use.  The Atik 16200 has a significantly higher cooling capacity (-50c against -38c) achieved by higher capacity fans and heat sink.  It is therefore a heavier camera - 1.3kgs against 0.9kgs.  Last night I noticed my guide stars were out of shape and when I checked that the guide camera was secure in its scope I could feel significant vibration on it.  This vibration was not in evidence in the main imaging optics, the focuser or the flatener but it was in the EFW3 and the camera.  It is there when the fans are running regardless of whether the cooler is engaged.  

I am not sufficiently expert to know but I cannot imagine such vibration is to be expected and I am sure it has been impacting my imaging performance.  One night my guiding bottomed out at 0.22" RMS but the corresponding 20 minute image had oval stars in it - which confused me.  At the time my thinking was that whilst the guidance may have been spot on and the main optics secure, something else in the imaging train must have been moving and now I have a chief suspect - but I really wouldn't know how to go about proving that or isolating it.

Is there anybody here who has any experience of the like, either with a 16200 or any other camera.  Do we think this is normal.  If not then as the camera is new I can go back to the vendor; if this is normal how does one damp out the vibrations?

Many thanks.

Gus

[RayD]

I use a 16200 and wouldn't say there is anything on the vibration front that woudl concern me, so it definitely doesn't sound right if you can feel the vibration in the filter wheel.

If the graph above is anything to go by, it certainly isn't having an adverse effect on anything though.

[Big Bang!]

Thank you.  The guiding is inconsistent though - it went from that to over 1.0" in half an hour and I cannot understand why.  With the above guiding performance I would have expected a perfect image but it wasn't.  Can you think of anything else that might cause a poor image with excellent guiding?  I am worried that there is something wrong with the camera.

Gus

[tooth_dr]

I am only throwing out a suggestion based on my recent experience.  I have a heavy load on my focuser, and in certain orientations, this causes tilt, which is visible in my OAG stars.  If I take a short or long exposure I have oval stars in the main camera image.  I track fine via PHD2 (not as good as yours but 0.6" or less), but because there is a tilt, it appears in all the images despite good guiding.  Once I flip to the other side of the pier, the stars are round again.  I guess the heavier camera might be an issue here?  Can you try comparing some short exposures?  Even post the image you have here along that you mentioned in the first post.  If I press my ear on to the scope (yes I did this) I can feel/hear the fan running, but it depends on your definition of 'significant' - if you set something light onto it can you see it move?

[Gorr_77]

Ive used Atik 16200 in high ambient temperatures with very steep time decline : minus 30 deg in several minutes and - yes it got very noisy but never shaky...i've had EEF2.2 and SX Fwheel  on ML focuser (check yours)...all very rigid.

[Skipper Billy]

The fans on mine run all the time but there is no noticeable vibration.

If your guiding is good (it is) but your stars are not then that would point to focuser droop/slop. IE the scope is pointing exactly where it should be but the camera is moving about.

[Big Bang!]

Thank you.  Yes, that all makes sense.  Comparing short exposures either side of the pier sounds like a good idea.

The vibration is instantly detectable through my fingers as soon as I touch either the EFW3, 16200 the or the guide camera so somehow it is being transmitted through about 18kgs of kit.  It is also faintly detectable when I touch the Esprit 120 itself.  Regardless of what is or is not happening with guidance, surely the camera should not be vibrating to the extent that the vibration is detectable through the filter wheel and into the optics?  My plan is to point the rig vertically and put a light class of water on the EFW to see if I can see any vibration on the surface.  

Any other ideas?

Gus

Edited May 29, 2020 by Big Bang!

[Big Bang!]

5 hours ago, Skipper Billy said:

The fans on mine run all the time but there is no noticeable vibration.

If your guiding is good (it is) but your stars are not then that would point to focuser droop/slop. IE the scope is pointing exactly where it should be but the camera is moving about.

My thoughts exactly.

 

Edited May 29, 2020 by Big Bang!

[Big Bang!]

Video of the vibrations

[Big Bang!]

On the left, 15 minutes unguided; PixInsight gives it .40 eccentricity.  On the right, taken immediately afterwards, 15 minutes guided with its guide data.  From a set up that bottomed out at 0.22" RMS last night.  

Gus

[RayD]

What mount is this?  I just can't see it being the camera vibrations causing this as it would have to be pretty bad and then I would expect it to be there in the non guided image.  Is this a separate guide scope or OAG?

[Big Bang!]

1 hour ago, RayD said:

What mount is this?  I just can't see it being the camera vibrations causing this as it would have to be pretty bad and then I would expect it to be there in the non guided image.  Is this a separate guide scope or OAG?

It's a 10 Micron 1000HPS, routinely guides to 0.5" and regularly does less than 0.3".  The new camera is the only change that could have any impact on it. Separate guide scope.  Same set up as before, which didn't have any of these issues. 

The vibration can barely be felt on the Esprit 120 itself but easily felt on its EFW and 16200.    However, it is most clearly felt on the guide camera and surely this has to be guidance related because the unguided is essential good?  Well, the only problem I can find on guidance is the vibration on the camera, everything else is the same as before the Atik 16200 upgrade.  If it is clear again tomorrow I may put the Atik One back on the rig and see if the issue is still present.

Gus

Edited May 30, 2020 by Big Bang!

[Big Bang!]

And here it is after a PHD reinstall and re-calibrate.

Gus

[RayD]

7 hours ago, Big Bang! said:

It's a 10 Micron 1000HPS, routinely guides to 0.5" and regularly does less than 0.3".  The new camera is the only change that could have any impact on it. Separate guide scope.  Same set up as before, which didn't have any of these issues. 

The vibration can barely be felt on the Esprit 120 itself but easily felt on its EFW and 16200.    However, it is most clearly felt on the guide camera and surely this has to be guidance related because the unguided is essential good?  Well, the only problem I can find on guidance is the vibration on the camera, everything else is the same as before the Atik 16200 upgrade.  If it is clear again tomorrow I may put the Atik One back on the rig and see if the issue is still present.

Gus

Well it certainly seems to be pointing to that as being the issue.  It must be pretty bad to be affecting the guiding this much so I would say it is definitely one or two faulty fans.

Drop Vince a line at Atik, he usually replies pretty quickly and will know for sure, but I definitely don't see this on mine, so it certainly can't be right.

Edited May 30, 2020 by RayD

[Gorr_77]

... 

6 hours ago, Big Bang! said:

And here it is after a PHD reinstall and re-calibrate.

Gus

...the only thing that moves fast is the fans, - faulty fan bearing? - Atik call as adviced

[Big Bang!]

1 hour ago, RayD said:

Well it certainly seems to be pointing to that as being the issue.  It must be pretty bad to be affecting the guiding this much so I would say it is definitely one or two faulty fans.

Drop Vince a line at Atik, he usually replies pretty quickly and will know for sure, but I definitely don't see this on mine, so it certainly can't be right.

Thank you all so much for your help - I am not sufficiently expert to be able to address such problems by myself.  

Having reinstalled and re-calibrated PHD2 the guidance stabilised at 0.3"RMS again - suggesting to me that it was a PHD issue and that guidance is not being impacted by the vibration off the 16200.

I am in discussions with Atik.

Gus  

Edited May 30, 2020 by Big Bang!

[Gorr_77]

2 minutes ago, Big Bang! said:

......Having reinstalled and re-calibrated PHD2 the guidance stabilised at 0.3"RMS again - suggesting to me that it was a PHD issue.......

Gus  

Ha! never thought of that.. great! Did they mentioned to you why PHD is doing it?

[RayD]

1 hour ago, Big Bang! said:

Thank you all so much for your help - I am not sufficiently expert to be able to address such problems by myself.  

Having reinstalled and re-calibrated PHD2 the guidance stabilised at 0.3"RMS again - suggesting to me that it was a PHD issue and that guidance is not being impacted by the vibration off the 16200.

I am in discussions with Atik.

Gus  

That's great news.  I did think it would have to be pretty bad to affect the guiding.

Glad you seem to be getting it resolved.  Atik aftercare is excellent and if it is an issue, as it seems to be if it is a visible vibration, then they will sort it, no question.

[Adam J]

On 30/05/2020 at 09:12, Gorr_77 said:

... 

...the only thing that moves fast is the fans, - faulty fan bearing? - Atik call as adviced

Not sure about that but its easy to get good tracking on a very saturated star as you cant detect its moving.

Looking at that occilation it remindes me of a positive feedback in the way it increases. I would say no way it is the fan as you would feel it virbating really obviously if it was causing 12 arcsecind errors. Or maybe the guide commands are out of phase with the reading somehow.

Edited May 31, 2020 by Adam J

[Big Bang!]

An update:  I had some further issues with poor guidance and would typically lose 50% of my frames due to seriously dreadful star shapes.  I tried guiding the rig with the 16200 switched off and then switched on to look for differences.  Instantly the problem was clear: the guide-star shape and profile were much fatter with the camera running but, when switched, off guidance dropped to 0.33RMS and the star profile shrank.   So in the end I had to send the 16200 back to Atik.  Really fabulous customer service at a difficult time for everybody.  They apparently found some play in the fan mounting and they replaced the fan itself. 

Just got it back; I have run the rig for 4 hours on 15 minute exposures starting low in the sky and working up to 55 degrees.  There is still a minor vibration on it (just visible in the PHD2 profile) but it is barely noticeable and my stars are now perfectly round over 15 min exposures.  Thus far I haven't lost a single frame and the guidance is good even when low down.  

So a big thank you to Atik. 😅

Gus