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What is my problem?

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#1 dron2015

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Posted 11 May 2021 - 12:32 AM

Hi Fellows,

 

Hope that you have been enjoying with the clear and deep dark skies!

 

Could please anyone advise - what is my problem here? Recently switched to QHY 600M and from time to time do see frames as this one. perhaps one in 50-100 frames goes such as this one...

 

1. always the same "breaks" - on the same places - my sensor is made of several smaller pieces?

2. why do I see it - is is some USB problem or something else? how to fix or alleviate it? I use shortest possible USB cable.

 

Besides these rare but weird frames I like QHY600M very much - frames are so clean that I am not even sure if I should care about the noise in PI at all.

 

Thank you!

 

Best,

Andrey

 

 

 

Attached Thumbnails

  • problem.jpg


#2 Birddogoby

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Posted 11 May 2021 - 02:33 AM

Audrey- I have a QHY600M and like you, I get the identical split image but very rarely.  From what others have said, it may be a USB related issue. Try changing up your USB traffic setting for the camera (I can change mine in NINA) and it may help.  I’ve only had it happen to me a couple of times in hundreds and hundreds of subs so I haven’t been too concerned about it.  Good luck!  Paul


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#3 michael8554

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Posted 11 May 2021 - 03:15 AM

ZWO too, I've had it occasionally on a  ASI 120MM guidecam, only left / right halves of frame swapped.


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#4 the Elf

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Posted 11 May 2021 - 03:34 AM

I've seen similar issues with industrial cameras. It is often caused by software engineers false assumption that the PC can process the input data fast enough at all times. Make sure your machine is on low load, no software or service running that you don't need. It could be a cable issue as well but more likely short load peaks on the computer.


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#5 dron2015

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Posted 11 May 2021 - 11:37 AM

Fellows, thanks much!  Will try to decrease a bit USB speed (as far as I remember - in SGP there is settings to control USB traffic) and will not be hard on my astro PC wrt gaming computing while capturing the data :)

 

Also I have beard that USB cable can create EM noise - my understanding that it is not USB or PC that are affected by the noise but rather USB cable serving as an antenna itself can induce radio noise and hope that it is not the issue in this particular case. anyway perhaps ferrite bead I should shop for as well.

 

I am wondering if anyone who uses ferrite chocks to suppress EM noise in USB have been facing this problem.

 

Best,

Andrey



#6 belliott4488

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Posted 11 May 2021 - 01:37 PM

Here's what I get when I swap the two sides of the lower portion (no surprise here, I suspect):

 

reassembled


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#7 dron2015

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Posted 11 May 2021 - 02:04 PM

Here's what I get when I swap the two sides of the lower portion (no surprise here, I suspect):

 

Bruce,  thanks much!  yes, it is Leo's triplet I am capturing :)


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#8 dron2015

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Posted 11 May 2021 - 02:05 PM

By the way, I have completely unnoticed that till now that two pieces were swapped in this weird frame!  thanks a lot!


Edited by dron2015, 11 May 2021 - 02:05 PM.


#9 davidmalanick

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Posted 11 May 2021 - 02:32 PM

https://www.qhyccd.c...catid=31&id=346

 

USB problem.  Happened to me. Noticed USB cable could wiggle just a bit on my laptop. New USB cable and now I use a piece of gaffer tape to hold cables tight to laptop, USB hub, etc.  No more problems.


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#10 kathyastro

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Posted 11 May 2021 - 03:06 PM

My ASI120MC does this from time to time.  It is definitely a USB problem.  The driver has a setting where you can slow down the USB traffic, and that helps.  It also helps to put the camera on its own USB line that is not shared with any other devices.  I have two USB cables running to the mount: one for the camera, and one for everything else.


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#11 dron2015

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Posted 11 May 2021 - 07:19 PM

Dear all,

 

 thanks much for pointing out to USB as a problem source!  I appreciate it very much!

 

1. I have shortest possible USB cable  length for my camera

2. I have nothing else on this USB cable - no guiding, no focuser - nothing. (like KathyAstro I also have 2 USB lines   - one for main camera and another for everything else)

3. I believe that I have quite good USB cable - manufactured by Cable Matters. If anyone has other ideas about good USB cable - I would appreciate advice

4. Camera - has its own power supply - not so bad AC adapter from Pegasus - no sharing power with other devices and I guess it is well grounded (one of the reasons mentioned on the link David provided - bad grounding)

5. USB hub. Yes, I do have it - it is internal USB cabling in my mount. However only this camera on USB 3.0. Cannot remove it or substitute - it is going to be major mess with cables.

 

David Malanick, if you could share the picture of your setup - "gaffer tape to hold cables tight to laptop, USB hub, etc" - i would appreciate it very much!

 

Perhaps I should double check cable connection and add some gaffer tape and perhaps ferrite chokes.

 

Best,

Andrey



#12 davidmalanick

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Posted 12 May 2021 - 01:35 PM

Dear all,

 

 thanks much for pointing out to USB as a problem source!  I appreciate it very much!

 

1. I have shortest possible USB cable  length for my camera

2. I have nothing else on this USB cable - no guiding, no focuser - nothing. (like KathyAstro I also have 2 USB lines   - one for main camera and another for everything else)

3. I believe that I have quite good USB cable - manufactured by Cable Matters. If anyone has other ideas about good USB cable - I would appreciate advice

4. Camera - has its own power supply - not so bad AC adapter from Pegasus - no sharing power with other devices and I guess it is well grounded (one of the reasons mentioned on the link David provided - bad grounding)

5. USB hub. Yes, I do have it - it is internal USB cabling in my mount. However only this camera on USB 3.0. Cannot remove it or substitute - it is going to be major mess with cables.

 

David Malanick, if you could share the picture of your setup - "gaffer tape to hold cables tight to laptop, USB hub, etc" - i would appreciate it very much!

 

Perhaps I should double check cable connection and add some gaffer tape and perhaps ferrite chokes.

 

Best,

Andrey

Rap the tape around the USB end, insert and pull tight while sticking the tape down.  Cables won't go anywhere or disconnect while slewing scope or cause a annoying random disconnect .  Gaffers tape is sticky but comes off like painters tape.  A bit pricey but worth it.
 

 

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#13 dron2015

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Posted 12 May 2021 - 09:34 PM

Rap the tape around the USB end, insert and pull tight while sticking the tape down.  Cables won't go anywhere or disconnect while slewing scope or cause a annoying random disconnect .  Gaffers tape is sticky but comes off like painters tape.  A bit pricey but worth it.
 

 

 

David, thanks much! will do! it would be a complete dissaster to lose NB frame, which could be an hour of time to make!

 

thank you for sharing your approach! I will do the same.



#14 my-spot

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Posted 13 May 2021 - 06:11 PM

Dr Qui himself gave an explanation for this in the following post...

 

https://www.cloudyni...ems/?p=11043934


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#15 rgsalinger

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Posted 13 May 2021 - 07:09 PM

What I did to get around this is simply to use USB 2 cabling. This added exactly 2 seconds to how long my downloads took. That makes sense if you do the numbers. 

 

I don't do high frame rate imaging so USB 2 is entirely adequate for my needs. I have not had one frame that looks like this since I made the change over a year ago. (I have the early bird version of the QHY600.)

 

I am now a zealous defender of the advantages of USB 2 as we await the coming of ethernet ports on all cameras, focusers, mounts and any other conceivable astro-photography component. 

 

Rgrds-Ross



#16 the Elf

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Posted 14 May 2021 - 01:46 AM

Ethernet connections do suffer from the same problems because the principle of data sent in packages is the same. Ethernet is on the other hand specified for up to 150m cable length. In all cases (USB2, USB3, Ethernet) software design can entirely prevent this. Dr. Qui would be well advised to implement a resend request in the driver when a CRC error occurs. Professional cameras do this and report statistics to the user. When you see resent packages you know there is a problem but the frame is not lost. Only if a resend fails multiple times the frame is lost. The point is, there is no false data send up to the application, a broken frame is detected and not used. Ross is right is saying USB2 is more robust (I feel bad using this word for USB at all) than USB3. It is also less demanding to the computer. USB2 transfers some 60Mb/sec so it is easy to do the math how long a single frame takes. GigE by the way is only some 115Mb/sec, not quite twice as fast as USB2. USB3 is faster than GigE. Some GigE camera have connectors with two thumb screws that do not drop out. USB can also be routed via custom plugs that have some sort of locking. I'd like to see that amateur cameras come up with this sort of connector.

If I was to design an astro camera it'd have a micro SD card slot and a threaded connection to the guide cam and the mount and do all the guiding and dither stuff on board. A computer link would be optional. Send job offers via PM, please. :-)


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#17 dron2015

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Posted 14 May 2021 - 03:27 PM

Fellows,

 

thanks much!  As of this moment  I decreased USB traffic in SGP to 40% and added ferrite chokes. No help - the issue resurfaces but still rare.

 

My next steps - to decrease traffic further and attach wires with some sticky tape (thanks much David for the suggestion!), if it does not help, I will switch to USB 2.0 (thanks much Ross!).

 

I agree with the Elf (my apologies - do not know your name) it is ridiculous that this technical problem is not yet tackled. Perhaps there are certain reasons, other than glorious laziness, but for an as ignorant person as myself it is quite "obvious" to add some checking routine to ensure that there were no errors during download if there were errors to do download again. the camera has the buffer. Maybe adding this routine will increase the traffic time? - i do not see how... surely it is obvious and if not correct here should be the reasons.

 

As of now, I am a bit disappointed - I have to check now all bias, dark, flat frames in addition to the lights and remove the bad frames manually :(  I am surely doing in PI blink (image inspection) but still another effort - something I never did with my ZWO 1600M. otherwise QHY600M is a great camera! I really like it very much and will not switch back to ZWO 1600M :)

 

Thank you and Clear Skies!

 

Best,

Andrey



#18 the Elf

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Posted 14 May 2021 - 04:39 PM

Elf is fine, even my GF calls me so. I guess for price reasons they just grabbed a readily available chip for USB and do not deal with low level data at all. As long as it is one in a million in a video stream it does not matter. If you loose a 20min NB shot that sucks. I'm still pretty sure it is not an electrical problem, neither loose plugs nor electromagnetic compatibility that can be cured by ferrite. I think it is a timing issue of some kind.

The 1600 is not an alternative anyway because of the square artifacts caused by the mircro lenses. PI should kick out the frame during star alignment because it cannot be aligned to the others. Did you check what happens if you leave it in the data set?

I agree, for bias and darks you have to check using blink. It is kinda frustrating if new gear has flaws like this. It is probably a problem of our consumer society with ever shorter innovation cycles. Even if an engineer wants to provide good work he/she is forced to hurry through the process to launch the product "in time", whatever that may mean. I confess my work could be way better but the company I work for does not want me to do good work. Only the figures count. It won't be much different at QHY or any other company.


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#19 dron2015

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Posted 14 May 2021 - 10:12 PM

PI should kick out the frame during star alignment because it cannot be aligned to the others

...

Even if an engineer wants to provide good work he/she is forced to hurry through the process to launch the product "in time", whatever that may mean. I confess my work could be way better but the company I work for does not want me to do good work. Only the figures count.

as for the darks, bias and flats, I do not use any rejection algorithms  so these masters are heavily affected if defected frames were not removed. Lights.... Frankly - do not solidly remember - I do remember some errors warnings but was not sure if PI excluded them from the registration output.  I removed them manually - but perhaps I shall double check.

 

yes, unfortunately all these 'innovation cycles' do push engineers and managers to bring to the market less than a perfect product. there are pros and cons surely. we have all seen how terribly it played with Boing corp w/ 737 max. Luckily, application of this camera is not critical.

 

Best,

Andrey

 

Best,

Andrey




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