ASI 1600MM Pro patter noise issue

Are you dithering?

No, I didn't use dithering so far. I will try it the next time to see if it makes a difference.

@jarbi58,

Hi Janos,

I'll have a look at the files. I have a ASI 1600mm-c myself. Not the Pro, but I believe the first version.

Like Greg indicated, what you are seeing is probably the result of not dithering and not using a Bad Pixel Map. It seems that the non-linear hot pixels are burning stripes in the integration because the images are shot with little movements between the exposures and all movements are in the same direction.

Which gain and offset did you use?

Cheers,

Mabula

Hi Mabula,

Thanks for your reply ! In between I have done more imaging with the camera by using a full calibration set, and it looks better:  https://www.astrobin.com/333551/?nc=user. However I am not yet convinced.

Since I am mostly working with multiple camera's at the same time, dithering is not an option for me. The reason is : there is no way to "synchronize" the start/stop times of the exposures between multiple camera's. So I will try to gather more experience with the ASI 1600 MM Pro, hopefully it was only a processing problem,

Clear skies,

Janos

If you use same guide camera, or not, should be able to dither with PhD and the image capturing software? If it is just an issue of dither recovery time that can't be tweaked no? Sorry if I seem persistent but it seems like that would make this all go away. I've been thinking of getting this camera.

This is an issue that a lot of ASI1600MM-Pro users have had... myself included. Here is a post over at ZWO's forum where a few of us talked about it:
http://bbs.astronomy-imaging-camera.com/viewtopic.php?f=21&t=7644
I contacted ZWO and sent them some of my FITS files and they determined there was a hardware issue with the camera. If you have just recently purchased the camera from a good dealer then you might be able to exchange it. If not I think you have to send it to ZWO. I think I saw somewhere that they mentioned it was an internal power issue. But can't find that link now.

I exchanged my camera because I had just purchased it and the new one works wonderfully.

Good luck!

Posted by: gdwats@comcast.net

If you use same guide camera, or not, should be able to dither with PhD and the image capturing software? If it is just an issue of dither recovery time that can't be tweaked no? Sorry if I seem persistent but it seems like that would make this all go away. I've been thinking of getting this camera.

Hi,

Maybe I was not clear what I have ment with multiple camera's: I am imaging with multiple ( 2 or 3 ) camera's at the sametime. That's why I'm saying that dithering is not an option for me. I am still trying to eliminate the pattern noise by using different ways of processing. This evening I was using sigma stacking for my bias and dark frames - didn't give better results. I have found several reports of this phenomenon ( a "random issue" according to ZWO ), I will maybe request a replacement.. 

Oh, I do see. Yes that could present a problem. I don't know of any other way though to deal with a cumulative fixed Point noise, other man to turn the background completely black almost. Clip clip clip bad practice. Good luck with the return if that's the solution. I have a feeling it is not. Some Noise can be cleaned up with lots and lots and lots of Subs but I don't think this type can. Mabula may know better tricks.

I use apt for a DSLR myself, but it also can handle CCD and multiple cameras. Perhaps you should look into it? Here is a link

https://ideiki.com/astro/usersguide/multi_camera_operation.htm

I haven't looked into it but perhaps one camera could pause while the other one is dithering and vice versa. Another option would to be if your exposure times differ because of sensitivities maybe you could have one take 15-minute pictures the other takes 30min,  set the first one to dither every two images something along those lines

Hi,

Thanks for your tip, I will look at it. I have already contacted ZWO and Sam advised to request a camera replacement, I will do that first. Normally I would expect that dithering is not necessary at all with this camera.

Posted by: Dennis

This is an issue that a lot of ASI1600MM-Pro users have had... myself included. Here is a post over at ZWO's forum where a few of us talked about it:
http://bbs.astronomy-imaging-camera.com/viewtopic.php?f=21&t=7644
I contacted ZWO and sent them some of my FITS files and they determined there was a hardware issue with the camera. If you have just recently purchased the camera from a good dealer then you might be able to exchange it. If not I think you have to send it to ZWO. I think I saw somewhere that they mentioned it was an internal power issue. But can't find that link now.

I exchanged my camera because I had just purchased it and the new one works wonderfully.

Good luck!

@sprinklestudios, thank you for sharing this.

@jarbi58, according to Dennis, a replacement indeed might be needed. Do let us know if the problem still persists or is solved when you get the replacement.

Mabula

Thanks Mabula, I also saw the post and requested replacement