Has anyone seen this problem before? QHYCCD QHY600PH M · John Hayes · ... · 52 · 3175 · 10

Bob Lockwood:
Hi John,

I know this dosen't help, but why did you stop using the FLI ML-16803. I use the PL-16803 and it's unlikely I will go QHY or ZWO. Just because it's a 9um chip
dosen't mean it can't get really good detail, and the chip is much bigger then the 455 chip, and it's very unlikely the FLI camera will ever have issues.

Michael & Jon Norman:
Hi John.

We may have seen something similar a few nights ago. I see you're using Maxim DL and have tried SGP.

We are using Voyager for image capture (and most everything). For the most part, it has been working very reliably. The other night, though, it started recording "dark" frames that may have been very similar to what you're seeing. We haven't looked too closely at the bad frames. They weren't all zeros, but I'm not sure if they were recording any meaningful signal. We'll look at some of them to gain some more insight. The strange thing is that it seemed to happen on a filter change. i.e. a long sequence of 180s L frames was fine, but shifting to 300S R/G/B frames resulted in the errant behaviour.

Voyager wasn't re-started before running the night's sequence when this happened.

Re-starting Voyager (and re-booting the mini-pc) seemed to cure it.

I haven't reported it to Voyager as it hasn't happened since and it seems better practice to re-start the imaging software each night. I suspect some sort of "memory leak" or driver initialization problem as opposed to a power / USB / other hardware issue. We do use a Pegasus Ultimate Powerbox, so we can remotely power cycle and "reset" USB connections.

I know this is a lot of detail for a problem that might have nothing to do with what you're experiencing, but my point is that it could as easily be a software "glitch" as hardware.

QHY suggests using their software to test their cameras ... I'd try using EZCap to test it. If you still have problems, it's likely time to get QHY support. They've been really good at diagnosing problems remotely for us.


​​​​Hope this helps.

Michael and Jon Norman

John Hayes:

Bob Lockwood:
Hi John,

I know this dosen't help, but why did you stop using the FLI ML-16803. I use the PL-16803 and it's unlikely I will go QHY or ZWO. Just because it's a 9um chip
dosen't mean it can't get really good detail, and the chip is much bigger then the 455 chip, and it's very unlikely the FLI camera will ever have issues.

Bob,
I agree that the FLI cameras are superb and I happen to have two FLI-ML16803s on the shelf in my shop.  I even started with that camera on this scope.  However, there were some solid reasons to go with the IMX455 sensor with this scope in Chile.  I've given a number of talks on this subject.  One is here:  https://www.optics.arizona.edu/news-events/events/opti617-public-talk-john-hayes-optics-adventures-during-pandemic-engineering-remo.   You can get a brief intro to the subject in this write up here:  https://www.optics.arizona.edu/news-events/events/opti617-public-talk-john-hayes-optics-adventures-during-pandemic-engineering-remo.  

John

John HayesNow I'm really puzzled.  The camera has worked just fine for the last two nights.  If it weren't for the fact that the problem went away on the first night after we swapped cables, I would conclude that the camera window had frosted over.  This camera might be old enough to require a new desiccant pellet and if the humidity were sufficiently high, frost could have formed.  I don't know.   I didn't mention that when I was first having the problem, I slewed over to the moon and took a few images, which were sharp enough to rule out frost.  If it keeps working, I'm ok with that but this problem will be in the back of my mind going forward.  Weird.


John



You'll need this plug and some desiccant pellets.

https://www.amazon.com/Wisedry-Rechargeable-Desiccant-Indicating-Reusable/dp/B01M7V19JE/ref=sr_1_11?crid=TANO8OCBM4MK&keywords=dessicant&qid=1667665432&sprefix=dessican%2Caps%2C148&sr=8-11

I use these and now the plug is on permanently. 
There is nothing inside the camera. My QHYs usually lasted 6 months before a recharge.




--Rouz

Scott Lockwood:
Hi John
 Clicking on the two links you show in your response to Bob, I get "page not found"
Is there a new link?

Scott

Rouz Astro:
*It does look too even to be frost which usually starts at the center of the window being furthest away from the heated edges of the glass.

Michael & Jon Norman:
The missing DLL message and EZCAP not starting sounds like a telltale sign of a software configuration problem to me that might be at the root of your problems. Did EZCAP work previously?

I know it's a pain to mess with, but it's a lot less of a pain than having to make the trip to Chile.

Totally understand that swapping in a working camera is better / quicker than going through the warranty cycle. We've taken the same approach. 

M & J

I had a different problem with my QHY600PH-M (random horizontal banding noise, like this guy: https://www.cloudynights.com/topic/700917-qhy168c-randomized-horizontal-banding/) and it too had to be sent back for repairs (from Chile as well...). I have a suspicion that the data during the USB transfer has neither error detection nor error correction, making me question the quality of the data and the applicability for remotely controlled telescopes that must operate reliably. I'm getting a replacement now and I pray to god that similar errors do not occur again

Björn:
After reading people pondering on power supply issues, I think about the power grid quality in general. I admit, I don't know about the conditions down there in Chile and how the hosting company deals with power supply for your scope. I am just projecting some personal experience from the Caribbean onto it: I would use a good and strong line filter to protect the equipment from misbehaviour or damage.
I know you thoroughly prepared for this endavour and if that point is checked already, just dismiss my comment on it.

John Hayes:
A couple of months ago my ATIK Horizon 2 guide camera started acting "wonky."  The background level suddenly went way up.  I mitigated it by subtracting a dark frame but it has screwed up the SNR of my guide signal.  Fortunately it still works well enough to guide.  Fortunately, I already have a replacement camera sitting at the observatory ready to be installed.  This is the second failure of a Horizon 2 in less than a year.

Just last night my main imaging camera, a QHY600PH M, went "wonky" in a different way.  It almost looks as if the 16 bit image data has been bit-shifted left by ~ 4-5 bits--but that's not what is happening. We fixed it last night by pulling and reconnecting cables but I'm out of luck tonight.  I can't get it to work correctly.  Here is a comparison of two images of the same object through a LUM filter at the same cooling temperature with the same exposure before and after the "glitch".



Here are histogram plots of both images.  First, before:



And second, after the failure:



There is no dew and the sky is clear.  This sure looks like a camera problem.  As I said, we fixed it last night by pulling cables and reconnecting them.  I've also tried a brand new USB3 cable with no improvement.  We haven't yet measured the voltage at the camera so that might be a problem.  This particular data was taken using MDL but I get the exact same results using SGP (my normal imaging program).

My question:  Has anyone else seen this problem and is there a simple fix?  I want to exhaust all possibilities before jumping on a plane to go to Chile with a replacement camera.  With two dead cameras, I'm already mentally packing my bags.


John