Banding issues with ASI 178MC: Page 2

Banding issues with ASI 178MC

tomr

I’ve plugged my ASI 178mc with it’s USB 3 cable into a free USB 2 port of my computer and recorded a series of dark frames. The banding pattern is indeed almost completely gone and it is now possible to record something else than Stars and Stripes. Even the noise floor of the histogram looks different from the pure USB 3 configuration. Since deep sky recordings do not require a lot of bandwidth, this should work for deep sky imaging, but it still has to be tested at night.

However, for planetary imaging with high framerate this USB 2 configuration is not sufficient. In its advertised USB 3 mode the camera seems to be very sensitive to electric interference or it has a driver problem. That sucks.

chad

Hi Carsten and TomR，

I'm still confused.

Can any of you send me an email? After we make an appointment, you can control my computer by remote control, and help me to reproduce it again. Is that ok?

I will focus on the work on the 178 camera next week, so I am looking forward to solving this problem together. Whether it is a hardware or software issue.

Email Address: chad.cao(at)zwoptical.com

Thanks

Chad

tomr

Hi Chad, I think you need some kind of integration test environment for your cameras, to check, if they can operate seamlessly together with other USB devices typically used to control amateur telescopes. It does not help much to test these things in a laboratory environment in a faraday cage.

In my case this is: a second cmos camera as telescope finder replacement, an external SSD drive, a dual-band wifi-antenna (in 1 m distance to pc), a telescope mount control via serial-to-usb bridge, a focuser control via serial-to-usb bridge. Besides that I’m using an electrical dew heater.

carsten

Hi Chad,

The problem only occurs for me, when there is a lot of traffic on the USB ports. In my case it's the ASI178 plucked to a USB3 port of my laptop (no SSD harddisc), my Star Shoot Autoguider Pro from Orion on an USB2 port and my Orion Atlas mount (identical to an EQ-6) controlled over cable with ASCOM.

My dew heaters are not USB powered, but with an external battery.

Simply switching the cable from USB3 to USB2 reduces the traffic enough to stop the problem.

When I just used my Go To controller and had only my mouse, guider and the ASI 178 plugged into the laptop, I didn't have these problems.

I live in Germany, I'm not so sure if it's doable time zone wise, but I'm willing to help, if I can.

chad

Hi Carsten，

Got your emails.

Sorry for this issue, and thanks again for your support :)

Thanks

Chad

tomr

Chad, I guess you haven't made any progress to verify the problem.

carsten

Hi Chad,

I'm sorry, but your mail ended up in my spam folder. I just found it and answered your questions in my new mail.

Sorry about the delay.

Support@ZWO

It's OK, never mind.

carsten

@TomR

My Turbo USB setting in Sharpcap was set to 96% instead of the default 80%. I don't know if this may have caused the banding, by creating too much traffic.

Do you use Sharpcap Tom? If yes, what is your Turbo USB setting?

I did some astro photography, but I got a new ASI 071 pro now and that didn't cause any banding or other problems whatsoever with the same laptop.

And it worked fine with Turbo USB set to 80%.

tomr

Carsten, I use Firecapture with it's default USB traffic settings for my recordings. USB traffic shouldn't be a problem for deep sky imaging with its low framerates, if the camera works reliably. I cannnot comment on the behaviour of other ZWO cameras, that's somewhat off topic.

tomr

I recall, that the developer of Firecapture wrote somewhere on the internet, that the ZWO cameras try to use all available USB bandwidth, even if it is not necessary for the active framerate and that this can cause problems on a lot of systems: dropped frames and image artefacts. I’m pretty sure, Confucius never heard of it.

Support@ZWO

That's not correct, USB bandwidth is adjustable in Firecapture and Sharpcap and ASICAP, etc.

If you set it at 100%, it will use full bandwidth, but also you can adjust it, it's control by softwares. It's not a camera defect.

tomr

These ZWO cameras are like a car with cruise control turned on to a factory preset speed limit of 55 mph. So if you turn on your ZWO engine and your car accelerates a lot to reach its preset speed limit and your car hits a pedestrian, this would be considered to be a weird behavior of the car and not a fault of the driver by most people. Confucius, on the other hand, might argue, that it’s your own fault, since you’ve got the possibility to reduce the speed limit to a lower level. However, in non-Confucius land, a car engine is supposed to run at its lowest stable level as long as the driver does not press the accelerator pedal. This weird behavior seams to be unique to ZWO cameras. Other manufacturers manage to build normal cameras that run on most computer systems without problems.

Support@ZWO

How about use USB3.0 try again. Maybe transmit speed is too slow under USB2.0 mode.

tomr

The banding pattern was present at the USB 3 port and USB traffic setting 60. The minimum USB traffic setting in Firecapture is 40, I guess. So there's little scope left for improvement. Besides that, it would be a highly unstable configuration.

It's your task to build usable cameras, not mine.

Support@ZWO

Please send us a email, Our engineer will contact with you directly. support(at)zwoptical.com

tomr

Current Email conversation status:

The banding pattern appears in stacked images taken with camera, e.g. at creation of a master dark. It seems to depend on the USB traffic settings. On my system it happens even at low USB traffic settings like the default value of 60 and it gets worse, if I increase that value. There are no lost frames, however.

The problem seems to be related to the fact, that your cameras clutter the USB bus, they produce more traffic than required to transmit the recorded images. So if you want to reproduce the effect, just plug in some other USB devices which use a lot of bandwidth (external SSDs, wifi-antennas etc.) and bring the USB bus to its limits.

shannonm

A friend in an AP group on FB pointed me to this thread, I had no idea this was a known issue with the ZWO ASI178mc. I have been incredibly disappointed with DSOs because the processing needed to bring out the details also amplifies the banding. Since this is my very first astronomy camera, I thought it was my lack of processing skills that left the banding behind. I had given up on DSOs with the 178mc, but I will try the USB2 solution to see if that helps any.

My current imaging setup has only the ZWO connected to my computer (via the USB3 port). I do not run my mount with my laptop nor do I have a guide camera connected (still saving up money for that). I get excellent results with the Sun in white light and of the Moon as well by taking ~2,000 frame videos and stacking them with AS!3, but I have not had one decent DSO image because of this banding. I get the banding whether I'm using FireCapture or SharpCap.

Frankly, I feel a little stunned right now. I got this cam because of the promise it worked well for DSOs as well as planetary but I have not found that to be the case at all. The banding has been there from the time I took my first image, this is not a new development for me. I have found a script in PixInsight that really helps ("Canon Debanding") but it's tedious to run on every single frame when you have hundreds.

Support@ZWO

Would you please send this camera back for repair? could you send a email to support(at)zwoptical.com?

tomr

A repair of the camera doesn't make sense, if you cannot reproduce the defect. What do you want to repair then?

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