Fixed Pattern Noise - ZWO 1600 MM Cooled Camera

rgsalinger

With short exposures I am getting a huge amount of fixed pattern noise. This is completely messing up my plate solving and my focusing. I'm attaching a screen shot of an example. What can be causing this?

The camera is 18 months old but was recently moved to a new location. The exposure was taken with the default unity gain settings. The USB traffic was 60 but reducing it to 40 made no difference. It is connected to the Versaplate on my MX+ and then to a second hub that goes to my PC.

Any insight would be appreciated. It appears to basically go away with longer exposures.

Rgrds-Ross

mcgillca

rgsalinger wrote:
With short exposures I am getting a huge amount of fixed pattern noise. This is completely messing up my plate solving and my focusing. I'm attaching a screen shot of an example. What can be causing this?

Rgrds-Ross

Dear Ross,

Hi - looks like you have this binned 2x2. What does this look like unbinned? I also came across a strange pattern in my images where every 8th column had almost zero values - it looks a lot like your image - see this post:

http://zwoug.org/viewtopic.php?f=21&t=7336http://zwoug.org/viewtopic.php?f=21&t=7336

My problem is intermittent - it came and went within one imaging session, was there for the next two days, then went again.

I did manage to platesolve though (I focus manually, so don't know if it causes a problem here). I'm a bit surprised that you are not able to platesolve the image you posted - I've seen TSX cope with much worse.

Colin

mcgillca

I should have added - do you get the same thing in your bias frames? If so, you could try auto calibrating the image with the bias frames as a way of taking this out, though it might be a pain if you only want to do that in your platesolving images.

Colin

rgsalinger

Bias frames are clean. Long exposures look fine. Focusing is where the problem occurs. I may try binned focusing and see if that works better. When plate solving, it just takes longer and things look weird but it works as far as I can tell. I was hoping that this was symptomatic of the need for a firmware upgrade, but I don't see one anywhere on the website.

Sam@ZWO

how is it without cooling?

it looks like some pin of the sensor didnot connect very well

rgsalinger

https://www.flickr.com/photos/rgsalinger/37471982541/in/dateposted-public/ is illustrative of the problem I keep having with the ASI1600MM-C. This just keeps coming and going. It will work for a day or two and then the lines reappear. I'm pretty certain that it needs to be fixed. Any and all comments appreciated. Unlike my original post this now appears (when it happens) in exposures of any bin level and any duration. I keep thinking that there's some secret setting that gets turned on and off or that there may be newer firmware that could cure the problem.

Rgrds-Ross